[Federal Register Volume 90, Number 179 (Thursday, September 18, 2025)]
[Rules and Regulations]
[Pages 44969-44978]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-18082]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration

21 CFR Part 866

[Docket No. FDA-2024-N-3533]


Microbiology Devices; Reclassification of Antigen, Antibody, and 
Nucleic Acid-Based Hepatitis B Virus Assay Devices

AGENCY: Food and Drug Administration, Department of Health and Human 
Services (HHS).

ACTION: Final amendment; final order.

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SUMMARY: The Food and Drug Administration (FDA) is issuing a final 
order reclassifying qualitative hepatitis B virus (HBV) antigen assays 
(product code LOM), HBV antibody assays (product code LOM), and 
quantitative HBV nucleic acid-based assays (product code MKT), all of 
which are postamendments class III devices, into class II (special 
controls), subject to premarket notification. FDA is also establishing 
the special controls that are necessary to provide a reasonable 
assurance of safety and effectiveness of these device types.

DATES: This order is effective October 20, 2025. See further discussion 
in Section IV, ``Implementation Strategy.''

FOR FURTHER INFORMATION CONTACT: Bhawna Poonia, Center for Devices and 
Radiological Health, Food and Drug Administration, 10903 New Hampshire 
Ave., Bldg. 66, Rm. 3226, Silver Spring, MD 20993, 240-402-6830, 
[email protected].

SUPPLEMENTARY INFORMATION:

I. Background--Regulatory Authorities

    The Federal Food, Drug, and Cosmetic Act (FD&C Act), as amended, 
establishes a comprehensive system for the regulation of medical 
devices intended for human use. Section 513 of the FD&C Act (21 U.S.C. 
360c) established three classes of devices, reflecting the regulatory 
controls needed to provide reasonable assurance of their safety and 
effectiveness. The three classes of devices are class I (general 
controls), class II (special controls), and class III (premarket 
approval).
    Devices that were not in commercial distribution prior to May 28, 
1976 (generally referred to as postamendments devices) are 
automatically classified by section 513(f)(1) of the FD&C Act into 
class III without any action taken by FDA (or the Agency). Those 
devices remain in class III and require premarket approval,

[[Page 44970]]

unless and until: (1) FDA reclassifies the device into class I or II; 
or (2) FDA issues an order finding the device to be substantially 
equivalent, in accordance with section 513(i) of the FD&C Act, to a 
predicate device that does not require premarket approval. The Agency 
determines whether new devices are substantially equivalent to 
previously marketed devices by means of the procedures in section 
510(k) of the FD&C Act (21 U.S.C. 360(k)) and our implementing 
regulations (part 807, subpart E (21 CFR part 807, subpart E)).
    A postamendments device that has been initially classified into 
class III under section 513(f)(1) of the FD&C Act may be reclassified 
into class I or class II under section 513(f)(3) of the FD&C Act. 
Section 513(f)(3) provides that FDA, acting by administrative order, 
can reclassify the device into class I or class II on its own 
initiative, or in response to a petition from the manufacturer or 
importer of the device. To change the classification of the device, the 
new class must have sufficient regulatory controls to provide 
reasonable assurance of the safety and effectiveness of the device for 
its intended use.\1\
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    \1\ See section 513 of the FD&C Act.
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    FDA relies upon ``valid scientific evidence,'' as defined in 
section 513(a)(3) of the FD&C Act and 21 CFR 860.7(c)(2), in the 
classification process to determine the level of regulation for 
devices.\2\ In general, to be considered in the reclassification 
process, the ``valid scientific evidence'' upon which the Agency relies 
must be publicly available. Publicly available information excludes 
trade secret and/or confidential commercial information, e.g., the 
contents of a pending PMA (see section 520(c) of the FD&C Act (21 
U.S.C. 360j(c))).
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    \2\ Id.
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    Section 510(m) of the FD&C Act provides that FDA may exempt a class 
II device from the requirements under section 510(k) of the FD&C Act if 
FDA determines that a premarket notification (510(k)) is not necessary 
to provide reasonable assurance of the safety and effectiveness of the 
device type.
    On September 25, 2024, FDA published a proposed order \3\ in the 
Federal Register to reclassify qualitative HBV antigen assays (product 
code LOM),\4\ qualitative HBV antibody assays and quantitative assays 
that detect anti-HBs (antibodies to HBV surface antigen (HBsAg)) 
(product code LOM),\5\ and quantitative HBV nucleic acid-based assays 
(product code MKT) from class III to class II (89 FR 78265, the 
``proposed order'').\6\ FDA has considered the information available to 
the Agency, including the deliberations of the Microbiology Devices 
Panel (the ``Panel'') convened on September 7, 2023, to discuss the 
proposed reclassification of these devices, and considered comments for 
that meeting as well as comments received from the public docket on the 
proposed order (as discussed in Section II of this document), to 
determine that there is sufficient information to establish special 
controls to effectively mitigate the risks to health. FDA has also 
determined that based on this information that the special controls, 
together with general controls, provide a reasonable assurance of 
safety and effectiveness when applied to these devices.
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    \3\ The ``ACTION'' caption for this proposed order was styled as 
``Proposed amendment; proposed order; request for comments'' rather 
than ``Proposed order.'' Beginning in December 2019, this editorial 
change was made to indicate that the document ``amends'' the Code of 
Federal Regulations. The change was made in accordance with the 
Office of the Federal Register's (OFR) interpretations of the 
Federal Register Act (44 U.S.C. chapter 15), its implementing 
regulations (1 CFR 5.9 and parts 21 and 22), and the Document 
Drafting Handbook.
    \4\ FDA's Center for Devices and Radiological Health (CDRH) uses 
product codes to help categorize and ensure consistent regulation of 
medical devices. A product code consists of three characters that 
are assigned at the time a product code is generated and is unique 
to a product type. The three characters carry no other significance 
and are not an abbreviation. See FDA guidance entitled, ``Medical 
Device Classification Product Codes'' available at https://www.fda.gov/regulatory-information/search-fda-guidance-documents/medical-device-classification-product-codes-guidance-industry-and-food-and-drug-administration-staff.
    \5\ These devices are currently regulated under product code 
LOM, but upon the finalization of this action they will fall within 
the newly created product code SEI.
    \6\ In the proposed order, FDA proposed to reclassify 
``Hepatitis B virus antibody assays (including qualitative and 
quantitative anti-HBs)'' under the classification regulation 21 CFR 
866.3179. In this final order, FDA is simplifying the identification 
of the classification regulation name to ``Hepatitis B virus 
antibody assays'' and adding further description to the 
identification language to better describe the devices that fit 
within this generic device type and are subject to this 
reclassification order. In addition, in the proposed order, FDA 
proposed to reclassify qualitative hepatitis B virus antigen assays 
under new classification regulation 21 CFR 866.3178 and quantitative 
hepatitis B virus nucleic acid-based assays under new classification 
regulation 21 CFR 866.3180. However, at the time of publication of 
this final order, a different regulation has been codified at Sec.  
866.3180. Therefore, in this final order, FDA is reclassifying these 
device types under different sections of the Code of Federal 
Regulations than was proposed in the proposed order. Specifically, 
FDA is reclassifying qualitative hepatitis B virus antigen assays 
under new classification regulation 21 CFR 866.3172, hepatitis B 
virus antibody assays under new classification regulation 21 CFR 
866.3173, and hepatitis B virus nucleic acid-based assays under new 
classification regulation 21 CFR 866.3174.
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    Therefore, in accordance with section 513(f)(3) of the FD&C Act, 
FDA, on its own initiative, is issuing this final order \7\ to 
reclassify qualitative HBV antigen assays, HBV antibody assays, and 
quantitative HBV nucleic acid-based assays \8\ from class III 
(premarket approval) to class II (special controls). Absent the special 
controls identified in this final order, general controls applicable to 
these device types are insufficient to provide reasonable assurance of 
the safety and effectiveness of these devices. FDA expects that the 
reclassification of these devices will enable more manufacturers to 
develop these types of devices such that patients will benefit from 
increased access to safe and effective diagnostics.
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    \7\ FDA notes that the ``ACTION'' caption for this final order 
is styled as ``Final amendment; final order,'' rather than ``Final 
order.'' Beginning in December 2019, this editorial change was made 
to indicate that the document ``amends'' the Code of Federal 
Regulations. The change was made in accordance with the Office of 
Federal Register's (OFR) interpretations of the Federal Register Act 
(44 U.S.C. chapter 15), its implementing regulations (1 CFR 5.9 and 
parts 21 and 22), and the Document Drafting Handbook.
    \8\ We use the phrase ``quantitative HBV nucleic acid-based 
assays'' to refer to the devices being reclassified in 21 CFR 
866.3174 Hepatitis B virus nucleic acid-based assays.
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    For these class II devices, instead of a PMA, manufacturers may 
submit a premarket notification and obtain FDA clearance of the devices 
before marketing them. This action will decrease regulatory burden on 
industry, as manufacturers will no longer have to submit a PMA for 
these types of devices but can instead submit a 510(k) to the Agency 
for review prior to marketing their device. A 510(k) typically results 
in a shorter premarket review timeline compared to a PMA, which 
ultimately provides patients with more timely access to these types of 
devices.
    This final order is expected to result in decreased regulatory 
burdens for affected devices moved from class III to class II and is 
considered deregulatory under Executive Order 14192.

II. Comments on the Proposed Order and FDA Responses

A. Introduction

    FDA received more than 25 comments on the proposed order. The 
comment period on the proposed order closed on November 25, 2024. The 
majority of the comments received by the close of the comment period 
came from research, disease and patient advocacy groups, individual 
medical professionals and an association of health care organizations, 
patients, and members of the medical device industry. Many commenters 
provided multiple comments on one or more issues. Comments provided 
support for the proposed reclassification

[[Page 44971]]

as well as included recommendations for clarity.
    We describe and respond to the comments in Section II.B of this 
document. The order of the comments and our response to them is purely 
for organizational purposes and does not signify the comment's value or 
importance of the comment nor the order in which comments were 
received. Certain comments are grouped together under a single number 
because the subject matter is similar. Please note that in some cases 
we separate different issues discussed by the same commenter and 
designate them as distinct comments for purposes of our responses.

B. Description of Comments and FDA Response

    (Comment 1) FDA received numerous comments in favor of the proposed 
reclassification of qualitative HBV antigen assays intended for 
qualitative detection of HBV antigens as an aid in the diagnosis of 
acute or chronic HBV infection in specific populations, HBV antibody 
assays intended for use in the detection of antibodies to HBV, and 
quantitative HBV nucleic acid-based assays intended for use in the 
detection of HBV nucleic acid in specimens from individuals with 
antibody evidence of HBV infection, from class III to class II with 
special controls. Commenters stated they believe that special controls, 
along with general controls, could provide reasonable assurance of the 
safety and effectiveness of these devices. In addition, they believed 
that the decreased regulatory burden resulting from the 
reclassification could encourage further development of, and provide 
patients more timely access to, these devices.
    (Response 1) Based on the evidence considered, comments received in 
response to the proposed order, and the 2023 Panel deliberations (Refs. 
1 and 2), FDA agrees with the commenters that reclassification of 
qualitative HBV antigen assays, HBV antibody assays, and quantitative 
HBV nucleic acid-based assays from class III into class II and that 
special controls, in addition to general controls, can provide 
reasonable assurance of the safety and effectiveness of these devices. 
In addition, FDA expects that the reclassification of these devices 
would enable more manufacturers to develop them such that patients 
would benefit from increased access to safe and effective tests.
    (Comment 2) Many commenters emphasized the importance of Point of 
Care (PoC) tests, particularly for settings that do not have access to 
blood serum testing whether because of cost or patient hesitancy, for 
testing and treating patients at the same visit and reducing the risk 
of patients not returning for follow-up, and for increased mobility and 
portability. Several commenters suggested that FDA should consider a 
Clinical Laboratory Improvements Amendments of 1988 (CLIA)--waiver 
designation for hepatitis B testing to make PoC tests available.
    (Response 2) These comments are beyond the scope of FDA's 
reclassification order, which applies only to qualitative HBV antigen 
assays, HBV antibody assays, and quantitative HBV nucleic acid-based 
assays that have been previously approved by FDA. FDA has not approved 
any such assays as PoC tests or categorized them as CLIA waived. FDA 
agrees that PoC tests should increase access to testing and encourages 
the development of such tests in the future.
    (Comment 3) Several comments suggested that FDA set reasonable 
cutoff values for test sensitivity and specificity, and asserted this 
would make it feasible for a PoC test to be available in the United 
States, while limiting false positives and false negatives. Several 
comments also recommended information be provided, such as sensitivity 
and specificity benchmark values or a statement to guide clinicians on 
whether or not reflex testing is warranted, due to the potential for 
misleading results.
    One commenter stated that screening tests should have high 
sensitivity to reduce the incidence of false negative results. In 
situations where a hepatitis B PoC test may have lower sensitivity, the 
commenter further recommended inclusion of a statement that individuals 
should have lab-based triple panel confirmatory testing that includes 
testing for HBsAg, hepatitis B surface antibody (anti-HBs), and total 
antibody to hepatitis B core antigen (total anti-HBc) to definitively 
determine a person's hepatitis B status.
    (Response 3) As discussed in response to comment 2, PoC tests are 
outside the scope of this reclassification. Moreover, the Panel 
recommendations from the September 7, 2023, meeting were unanimous that 
performance expectations should not be compromised or lowered compared 
with approved tests (Refs. 1 and 2). The proposed special controls for 
qualitative HBV antigen assays and, when applicable, HBV antibody 
assays state that analytical sensitivity of the assay is the same or 
better than that of other cleared or approved assays. FDA has added 
this special control in Sec.  866.3174(b)(2)(ix) for HBV nucleic acid-
based assays because it was inadvertently omitted from the proposed 
order. FDA continues to believe that the special controls finalized in 
this administrative order are necessary and sufficient to provide 
reasonable assurance of safety and effectiveness for the HBV assays 
that are within the scope of this final order.
    The comments regarding providing sensitivity and specificity 
benchmark values to guide reflex testing and triple panel confirmatory 
testing are beyond the scope of this reclassification order as they 
relate to the practice of medicine and current Centers for Disease 
Control and Prevention (CDC) guidelines (Ref. 3). However, we note that 
such guidelines are useful to practitioners as they administer these 
tests and we acknowledged such guidelines in our proposed order.\9\
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    \9\ See 89 FR 78265 at 78271.
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    FDA also notes that the scope of the order is diagnostic devices 
reviewed by CDRH. Screening tests are not within the scope of the 
reclassification order as indicated by the identification of the 
respective classification regulations.
    (Comment 4) Several comments encouraged FDA to allow reliable data 
obtained from approved hepatitis B PoC tests used globally with success 
for many years when determining the required sample size within the 
United States.
    (Response 4) As discussed in response to comment 2, PoC tests are 
outside the scope of this reclassification because FDA has not approved 
qualitative HBV antigen assays, HBV antibody assays, and quantitative 
HBV nucleic acid-based assays as PoC tests. FDA has not specified a 
sample size requirement as a necessary risk mitigation in the proposed 
special controls or final special controls included within this final 
order. Regarding the utilization of data sourced from outside the 
United States, FDA has regulations on the acceptance of data from 
clinical investigations conducted outside the United States (OUS) to 
support marketing applications for devices and recommends that sponsors 
that include OUS data in their marketing application explain how the 
OUS data are applicable to the US population and US medical 
practice.\10\
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    \10\ See ``Human Subject Protection; Acceptance of Data from 
Clinical Investigations for Medical Devices'' (83 FR 7366) and FDA 
guidance entitled ``Acceptance of Clinical Data to Support Medical 
Device Applications and Submissions Frequently Asked Questions'', 
available at https://www.fda.gov/regulatory-information/search-fda-guidance-documents/acceptance-clinical-data-support-medical-device-applications-and-submissions-frequently-asked.

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    (Comment 5) Some commenters asked for clarification on whether the 
proposed reclassification is referring to all anti-HBV immunoassays, 
which would include the rapid serum assays commonly used in the 
inpatient setting. Commenters stated that it was unclear whether 
hepatitis B core antibody (HBcAb) Immunoglobulin M (IgM) and 
Immunoglobulin G (IgG), hepatitis B core antibody total (HBcAb total), 
and HBe antibody are included in the proposed reclassification.
    (Response 5) The identification language in the classification 
regulation for HBV antibody assays as stated in the proposed order and 
new Sec.  866.3173 states that an HBV antibody assay is ``intended for 
prescription use in the detection of antibodies to HBV in human serum, 
plasma, or other matrices, and as a device that aids in the diagnosis 
of HBV infection in persons with signs and symptoms of hepatitis and in 
persons at risk for hepatitis B infection'' (see Sec.  866.3173(a)). 
This classification regulation covers HBV antibody assay types approved 
to date and assigned to product code LOM,\11\ including serology 
devices that detect anti-HBc IgM, anti-HBc IgG, anti-HBc total, anti-
HBs and anti-HBe. To further clarify which devices are included within 
the classification, we are simplifying the classification regulation 
name to ``Hepatitis B virus antibody assays'' and explaining in the 
identification language that ``results from assays may be qualitative 
or quantitative, such as quantitative anti-HBs.'' The quantitative HBV 
antibody assays approved to date are quantitative anti-HBs. A 
quantitative HBV antibody assay other than for anti-HBs could also 
potentially fall within this classification regulation, if the device 
has the same intended use and does not raise different questions of 
safety and effectiveness.\12\
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    \11\ As noted elsewhere in this document, upon the finalization 
of this action these devices will fall within the newly created 
product code SEI.
    \12\ The statutory standard for establishing substantial 
equivalence is defined in section 513(i) of the FD&C Act and further 
described in FDA guidance entitled ``The 510(k) Program: Evaluating 
Substantial Equivalence in Premarket Notifications [510(k)], 
available at https://www.fda.gov/regulatory-information/search-fda-guidance-documents/510k-program-evaluating-substantial-equivalence-premarket-notifications-510k.
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    (Comment 6) One commenter encouraged FDA to continue post approval 
safety surveillance and consider implementing mandatory reviews by 
third parties at certain time intervals to ensure the specificity and 
sensitivity of these assays remain as initially reported.
    (Response 6) FDA notes there are various mechanisms in place to 
monitor the post market safety of devices. FDA maintains the MDR 
database, MAUDE database, and Medical Device Recall database, which 
allows for additional post-market surveillance of these devices and 
helps to ensure continued safety for marketed devices. For example, 
manufacturers are required to report to FDA information that reasonably 
suggests that their device may have caused or contributed to a death or 
serious injury, or has malfunctioned and the device or a similar device 
that the manufacturer markets would be likely to cause or contribute to 
a death or serious injury if the malfunction were to recur under 
section 519(a) of the FD&C Act (21 U.S.C. 360i(a)). Manufacturers also 
must report to FDA any correction or removal of a device undertaken to 
reduce a risk to health posed by the device, or to remedy a violation 
of the FD&C Act caused by the device which may present a risk to health 
under section 519(g) of the FD&C Act. Additionally, if a device's 
quality falls below that which it purports or is represented to 
possess, then it may be deemed to be adulterated under section 501(c) 
of the FD&C Act (21 U.S.C. 351(c)). In addition, routine or for-cause 
inspections, which may consider compliance with quality system 
requirements \13\ applicable to the device, allow for appropriate post-
market oversight of these devices with respect to inspections. Hence, 
FDA does not believe that additional postmarket special controls are 
necessary to provide reasonable assurance of safety and effectiveness 
for the HBV assays that are within the scope of this final order. The 
suggestion of mandatory reviews by third parties is outside the scope 
of this reclassification order.
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    \13\ On February 2, 2024, FDA issued a final rule amending the 
device Quality System Regulation, 21 CFR part 820, to align more 
closely with internal consensus standards for devices (89 FR 7496). 
This final rule will take effect on February 2, 2026. Once in 
effect, this rule will withdraw the majority of the current 
requirements in part 820 and instead incorporate by reference the 
2016 edition of the International Organization for Standardization 
(ISO) 13485, Medical devices--Quality management systems--
Requirements for regulatory purposes, in part 820. As stated in the 
final rule, the requirements in ISO 13485 are, when taken in 
totality, substantially similar to the requirements of the current 
part 820, providing a similar level of assurance in a firm's quality 
management system and ability to consistently manufacture devices 
that are safe and effective and otherwise in compliance with the 
FD&C Act.
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    (Comment 7) One comment stated that there should be clear 
instructions to inform individuals that hepatitis B testing performed 
during early infection may not accurately detect hepatitis B and it is 
critical for these individuals to be retested at the appropriate 
interval to reduce the likelihood of false negative results and missed 
diagnoses.
    (Response 7) FDA agrees with this comment. The special controls for 
the HBV antibody assays include labeling limitations that a ``non-
reactive assay result may occur early during acute infection, prior to 
development of a host antibody response to infection, or when analyte 
levels are below the limit of detection of the assay'' (see Sec.  
866.3173(b)(1)(iv)(E)). Additionally, the special controls for the HBV 
antigen assays include labeling limitations that state that a ``non-
reactive assay result does not exclude the possibility of exposure to 
or infection with hepatitis B virus'' (see Sec.  
866.3172(b)(1)(iv)(E)). Finally, the special controls include labeling 
limitations that indicate that ``[d]iagnosis of hepatitis B infection 
should not be established on the basis of a single assay result but 
should be determined by a licensed healthcare professional in 
conjunction with the clinical presentation, history, and other 
diagnostic procedures'' (see Sec.  866.3172(b)(1)(iv)(C); Sec.  
866.3173(b)(1)(iv)(D)).
    (Comment 8) One comment stated there is significant confusion among 
clinicians regarding when it is appropriate to order total antibody to 
hepatitis B core antigen (total anti-HBc, which is a measure of both 
anti-HBc IgG and anti-HBc IgM) testing and when to order hepatitis B 
core antibody IgM (anti-HBc IgM) testing and how to interpret the 
results. The commenter recommended the inclusion of clear instructions 
that clarify anti-HBc IgM testing align with CDC guidelines. Another 
comment also recommended clear instructions on when to test for and how 
to interpret the different types of hepatitis B core antibody tests.
    (Response 8) These comments regarding when to conduct total anti-
HBc testing or anti-HBc IgM testing based on CDC guidelines and 
recommendations for clear instructions on testing and interpretation of 
hepatitis B core antibody tests relate to medical practice guidelines 
and recommendations provided by professional organizations and are 
beyond the scope of this reclassification order. However, the special 
controls for HBV antibody assays include labeling to provide detailed 
explanation of the interpretation of results and limitations, which 
must be updated to reflect current clinical practice and disease 
presentation and management, that address result interpretation (see 
Sec.  866.3173(b)(1)(iii) and (iv)).

[[Page 44973]]

    (Comment 9) Another comment stated that for all positive PoC test 
results, there should be clear instructions on the type of testing 
necessary to confirm an individual's hepatitis B status. The commenter 
also stated that for negative PoC test results, the individual should 
be informed of the need for hepatitis B vaccination to prevent 
infection.
    (Response 9) These comments regarding confirmatory testing and 
medical practice and recommendations provided by professional 
organizations are beyond the scope of this reclassification order.
    (Comment 10) One comment requested that FDA consider expanding the 
regulation for quantitative HBV nucleic acid-based assays to include 
diagnostic use (independent of antibody status) for HBV infection in 
addition to monitoring. The comment stated that detectable HBV DNA is 
indicative of infection and can be used as a diagnostic marker. In 
addition, HBV DNA may be detectable sooner after infection than viral 
antigens and/or antibodies and therefore may enable earlier detection 
of infection or reactivation of infection.
    (Response 10) This comment is beyond the scope of this 
reclassification order, which applies only to nucleic acid-based HBV 
DNA tests for patient management that have been previously approved by 
FDA. FDA has not approved nucleic acid-based HBV DNA tests intended for 
diagnosis of HBV infection. Thus, this additional intended use is 
beyond the scope of FDA's reclassification order.
    (Comment 11) One commenter noted the special controls for HBV 
nucleic acid-based assays state that: ``Samples selected for use must 
be from subjects with clinically relevant circulating genotypes in the 
United States'' (see Sec.  866.3174(b)(2)(viii)). The commenter 
requested FDA clarify whether clinical specimens must be used for the 
analytical studies and whether samples contrived using pre-screened HBV 
negative clinical specimens containing clinically relevant circulating 
HBV genotypes in the United States could be used in analytical studies. 
The commenter suggested that FDA revise the statement to ``Samples 
selected for use in analytical studies or used to prepare samples for 
use in analytical studies must be from subjects with clinically 
relevant circulating genotypes in the United States.''
    (Response 11) FDA disagrees that such a clarification is needed. In 
the past, FDA has generally preferred native clinical samples to 
provide a reasonable assurance of safety and effectiveness for HBV 
assays. However, FDA has considered alternative approaches that used 
contrived samples in specific analytical studies with adequate 
justification, for example, see the Summary of Safety and Effectiveness 
Data for P190034 (Ref. 4).
    (Comment 12) One commenter supported FDA's proposal to reclassify 
certain hepatitis B assays from class III to class II and, citing human 
immunodeficiency virus (HIV), hepatitis and sexually transmitted 
infections, stated that FDA should continue to partner with the CDC, 
National Institutes of Health (NIH) and others to support additional 
research and interdisciplinary collaboration on these issues. The 
commenter also recommended that FDA and its partners evaluate the 
impact of this and other reclassifications in the context of other 
proposed or recently implemented changes, including those changes per 
FDA's January 31, 2024, announcement \14\ that it intended to initiate 
the reclassification process for most high risk IVDs, the majority of 
which are infectious disease and companion diagnostic in vitro 
diagnostic devices.
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    \14\ CDRH Announces Intent to Initiate the Reclassification 
Process for Most High Risk IVDs [verbar] FDA available at https://www.fda.gov/medical-devices/medical-devices-news-and-events/cdrh-announces-intent-initiate-reclassification-process-most-high-risk-ivds.
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    (Response 12) FDA appreciates these comments. FDA is undertaking 
this reclassification of certain HBV assays on its own initiative as 
reflected in the Agency's January 31, 2024, announcement. As warranted, 
FDA collaborates with other organizations such as CDC and NIH to 
support cross-cutting issues.
    (Comment 13) One commenter recommended that FDA introduce an app 
that would connect administrators, vaccine manufacturers, public and 
private vaccine facilities, vaccine recipients, etc. The commenter 
envisioned that the app would allow individuals to book and schedule 
online appointments for vaccination and obtain a vaccine certificate 
and track adverse events following immunization.
    (Response 13) This comment is beyond the scope of this 
reclassification order.
    (Comment 14) Several commenters also asked FDA to reclassify 
quantitative HBsAg assays and asserted these assays will be necessary 
to predict response and monitor efficacy of new therapies that are now 
in clinical testing if such therapies are approved. One commenter asked 
FDA to provide device classification if a rapid device is used in 
combination with other analytes such as HIV Ab, hepatitis C virus (HCV) 
Ab, or syphilis testing.
    (Response 14) FDA has not approved any quantitative HBsAg test, nor 
any HBV assay in combination with other analytes such as HIV Ab, HCV 
Ab, or syphilis testing, thus the comments requesting the 
reclassification of such devices are beyond the scope of this 
reclassification order.

III. The Final Order

    FDA is adopting its findings under section 513(f)(3) of the FD&C 
Act, as published in the preamble to the September 25, 2024 proposed 
order (89 FR 78265). FDA has made some minor revisions in this final 
order in response to comments received (see Section II). FDA is issuing 
this final order to reclassify qualitative HBV antigen assays, HBV 
antibody assays, and quantitative HBV nucleic acid-based assays from 
class III into class II under three new device classification 
regulations, and to establish special controls by revising 21 CFR part 
866 (adding 21 CFR 866.3172, 866.3173, and 866.3174, respectively).
    The qualitative HBV antigen assay is assigned the classification 
regulation name ``Qualitative hepatitis B virus antigen assays'' and it 
is identified as an in vitro diagnostic device intended for 
prescription use for qualitative use with human serum, plasma, or other 
matrices that aids in the diagnosis of chronic or acute HBV infection. 
HbsAg is also used for screening of HBV infection in pregnant women to 
identify neonates who are at risk of acquiring hepatitis B during 
perinatal period. The assay is not intended for screening of blood, 
plasma, cells, or tissue donors.
    The HBV antibody assay is assigned the classification regulation 
name ``Hepatitis B virus antibody assays'' and it is identified as an 
in vitro diagnostic device intended for prescription use in the 
detection of antibodies to HBV in human serum, plasma, or other 
matrices, and as a device that aids in the diagnosis of HBV infection 
in persons with signs and symptoms of hepatitis and in persons at risk 
for hepatitis B infection. Results from assays may be qualitative or 
quantitative, such as quantitative anti-HBs. In addition, results from 
an anti-HBc IgM (IgM antibodies to core antigen) assay indicating the 
presence of anti-HBc IgM are indicative of recent HBV infection. Anti-
HBs (antibodies to surface antigen) assay results may be used as an aid 
in the determination of susceptibility to HBV infection in individuals 
prior to or following HBV vaccination or when vaccination status is 
unknown. The assay is not intended for screening of

[[Page 44974]]

blood, plasma, cells, or tissue donors. The assay is intended as an aid 
in diagnosis in conjunction with clinical findings and other diagnostic 
procedures. The identification for Sec.  866.3173(a)(1) has been 
revised to provide a more accurate description of the devices in this 
classification regulation.
    The quantitative HBV nucleic acid-based assay is assigned the 
classification regulation name ``Hepatitis B virus nucleic acid-based 
assays'' and it is identified as an in vitro diagnostic device intended 
for prescription use in the detection of HBV nucleic acid in specimens 
from individuals with antibody evidence of HBV infection. In these 
devices, the detection of HBV nucleic acid is used as an aid in the 
management of HBV-infected individuals. The assay is intended for use 
with human serum or plasma (and other matrices as applicable) from 
individuals with HBV. The assay is not intended for use as a donor 
screening assay for the presence of HBV nucleic acids in blood, blood 
products, plasma, cells, or tissue donors, or as a diagnostic assay to 
confirm the presence of HBV infection.
    Based on the information discussed in the preamble to the proposed 
order, the comments received for the proposed order and the Panel 
meeting, and the 2023 Panel deliberations (Ref. 1 and 2), FDA concludes 
that special controls, in addition to general controls, provide a 
reasonable assurance of the safety and effectiveness of qualitative HBV 
antigen assays, HBV antibody assays, and quantitative HBV nucleic acid-
based assays. In this final order, the Agency has identified the 
special controls under section 513(a)(1)(B) of the FD&C Act that, along 
with general controls, provide a reasonable assurance of the safety and 
effectiveness of these devices. In this final order, FDA has added the 
special control at Sec.  866.3174(b)(2)(ix) to require that design 
verification and validation include analytical sensitivity of the assay 
that is the same or better than that of other cleared or approved 
assays because this special control was inadvertently omitted from the 
proposed order. In addition, FDA has simplified the classification 
regulation name in Sec.  866.3173 to ``Hepatitis B virus antibody 
assays'' and also clarified in the identification language which assays 
fall within the classification regulation. Finally, in this final 
order, to provide additional clarification and to efficiently implement 
this order, the Agency has added an implementation strategy in Section 
IV.
    FDA has also created a new product code SEI for HBV antibody 
assays. Qualitative HBV antigen assays will continue to be assigned the 
product code LOM. Quantitative HBV nucleic acid-based assays will 
continue to be assigned the product code MKT.
    Section 510(m) of the FD&C Act provides that FDA may exempt a class 
II device from the premarket notification requirements under section 
510(k) of the FD&C Act, if FDA determines that premarket notification 
is not necessary to provide reasonable assurance of the safety and 
effectiveness of the device.\15\ FDA has determined that premarket 
notification is necessary to provide a reasonable assurance of the 
safety and effectiveness of qualitative HBV antigen assays, HBV 
antibody assays, and quantitative HBV nucleic acid-based assays. 
Therefore, these devices are not exempt from premarket notification 
requirements. Thus, under sections 510(k) and 513(f) of the FD&C Act, 
persons who intend to market a device in any of these device types must 
submit to FDA a premarket notification, obtain clearance, and 
demonstrate compliance with the special controls included in this final 
order, prior to marketing the device.
---------------------------------------------------------------------------

    \15\ In considering whether to exempt class II devices from 
premarket notification, FDA considers whether premarket notification 
for the type of device is necessary to provide reasonable assurance 
of safety and effectiveness of the device. FDA generally considers 
the factors initially identified in 63 FR 3142 (January 21, 1998) 
and further explained in FDA guidance ``Procedures for Class II 
Device Exemptions from Premarket Notification, Guidance for 
Industry, and CDRH Staff'' to determine whether premarket 
notification is necessary for class II devices. FDA also considers 
that even when exempting devices from the 510(k) requirements, these 
devices would still be subject to certain limitations on exemptions, 
for example, the general limitations set forth in 21 CFR 866.9.
---------------------------------------------------------------------------

    Manufacturers may wish to use predetermined change control plans 
(PCCPs) as a way to implement future modifications to their devices 
without needing to submit a new 510(k) for each significant change or 
modification \16\ while continuing to provide a reasonable assurance of 
device safety and effectiveness.\17\ FDA reviews a PCCP as part of a 
marketing submission for a device to ensure the continued safety and 
effectiveness of the device without necessitating additional marketing 
submissions for implementing each modification described in the PCCP. 
When used appropriately, PCCPs authorized by FDA are expected to be 
least burdensome for manufacturers and FDA.\18\
---------------------------------------------------------------------------

    \16\ For the purpose of this final order reference to 
``modification'' means a significant change or modification that 
would generally require a new premarket notification under 21 CFR 
807.81(a)(3).
    \17\ Section 3308 of the Food and Drug Omnibus Reform Act of 
2022, Title III of Division FF of the Consolidated Appropriations 
Act, 2023, Public Law 117-328 (``FDORA''), enacted on December 29, 
2022, added section 515C ``Predetermined Change Control Plans for 
Devices'' to the FD&C Act. Section 515C has provisions regarding 
predetermined change control plans (PCCPs) for devices requiring 
premarket approval or premarket notification. Under section 515C, 
supplemental applications (section 515C(a)) and new premarket 
notifications (section 515C(b)) are not required for a change to a 
device that would otherwise require a premarket approval supplement 
or new premarket notification if the change is consistent with a 
PCCP approved or cleared by FDA.
    \18\ Sections 513 and 515 of the FD&C Act. See also, FDA's 
guidance ``The Least Burdensome Provisions: Concept and Principles 
[verbar] FDA''.
---------------------------------------------------------------------------

    Under this final order, these qualitative HBV antigen assays, HBV 
antibody assays, and quantitative HBV nucleic acid-based assays are 
prescription use IVD devices and as such, these assays must satisfy 
prescription labeling requirements for in vitro diagnostic products 
(see 21 CFR 809.10(a)(4) and (b)(5)(ii)). These device types would 
continue to be subject to the submission and device clearance 
requirements of sections 510(k) and 513 of the FD&C Act and of part 
807, subpart E.

IV. Implementation Strategy

    This final order is effective 30 days after the date of its 
publication in the Federal Register.
    For qualitative HBV antigen assays, HBV antibody assays, and 
quantitative HBV nucleic acid-based assays that have not been offered 
for sale prior to the effective date of the final order, or for devices 
that have been legally marketed via PMA before the effective date of 
this final order but the device is about to be significantly changed or 
modified per 21 CFR 807.81(a)(3) after the effective date, 
manufacturers must obtain 510(k) clearance, among other relevant 
requirements, and demonstrate compliance with the special controls 
included in this final order, before marketing the new or changed 
device.
    For qualitative HBV antigen assays, HBV antibody assays, and 
quantitative HBV nucleic acid-based assays that have been offered for 
sale prior to the effective date of the final order and have prior PMA 
approval, such devices may continue to be marketed per the previously 
approved PMA and do not require an additional marketing application. 
Any future changes to the device would be subject to 510(k) 
requirements and governed by 21 CFR 807.81(a)(3).

V. Analysis of Environmental Impact

    We have determined under 21 CFR 25.34(b) that this action is of a 
type that does not individually or cumulatively have a significant 
effect on the human

[[Page 44975]]

environment. Therefore, neither an environmental assessment nor an 
environmental impact statement is required.

VI. Paperwork Reduction Act of 1995

    This final administrative order establishes special controls that 
refer to previously approved collections of information found in FDA 
regulations. These previously approved collections of information are 
subject to review by the Office of Management and Budget (OMB) under 
the Paperwork Reduction Act of 1995 (44 U.S.C. 3501-3521). The 
collections of information in 21 CFR part 820 (Quality System 
Regulation) have been approved under OMB control number 0910-0073; the 
collections of information in part 807, subpart E (Premarket 
Notification Procedures), have been approved under OMB control number 
0910-0120; and the collections of information in 21 CFR parts 801 and 
809 (Device Labeling) have been approved under OMB control number 0910-
0485.

VII. Codification of Orders

    Under section 513(f)(3) of the FD&C Act, FDA may issue final orders 
to reclassify devices. FDA will continue to codify classifications and 
reclassifications in the Code of Federal Regulations (CFR). Changes 
resulting from final orders will appear in the CFR as newly codified 
orders. Therefore, under section 513(f)(3) of the FD&C Act, we are 
codifying in this final order the classification of (i) qualitative 
hepatitis B virus antigen assays in the new 21 CFR 866.3172; (ii) 
hepatitis B virus antibody assays in the new 21 CFR 866.3173; and (iii) 
hepatitis B virus nucleic acid-based assays in the new 21 CFR 866.3174, 
under which each of these device types are reclassified from class III 
into class II.

VIII. References

    The following references marked with an asterisk (*) are on display 
at the Dockets Management Staff (HFA-305), Food and Drug 
Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852, 240-
402-7500, and are available for viewing by interested persons between 9 
a.m. and 4 p.m., Monday through Friday; they also are available 
electronically at https://www.regulations.gov. References without 
asterisks are not on public display at https://www.regulations.gov 
because they have copyright restriction. Some may be available at the 
website address, if listed. References without asterisks are available 
for viewing only at the Dockets Management Staff. Although FDA verified 
the website addresses in this document, please note that websites are 
subject to change over time.

*1. Meeting Transcript Prepared for the September 7, 2023, Meeting 
of the Microbiology Devices Panel (available at https://www.fda.gov/media/173609/download).
*2. Summary Minutes Prepared for the September 7, 2023, Meeting of 
the Microbiology Devices Panel (available at https://www.fda.gov/media/173610/download).
3. CDC, ``Clinical Testing and Diagnosis for Hepatitis B,'' https://www.cdc.gov/hepatitis-b/hcp/diagnosis-testing/index.html. Accessed 
March 18, 2025.
*4. P190034 Summary of Safety and Effectiveness, available at: 
https://www.accessdata.fda.gov/cdrh_docs/pdf19/P190034B.pdf.

List of Subjects in 21 CFR Part 866

    Biologics, Laboratories, Medical devices.

    Therefore, under the Federal Food, Drug, and Cosmetic Act (21 
U.S.C. 321 et seq., as amended), and under authority delegated to the 
Commissioner of Food and Drugs, 21 CFR part 866 is amended as follows:

PART 866--IMMUNOLOGY AND MICROBIOLOGY DEVICES

0
1. The authority citation for part 866 continues to read as follows:


    Authority:  21 U.S.C. 351, 360, 360c, 360e, 360j, 360l, 371.

0
2. Add Sec.  866.3172 to subpart D to read as follows:


Sec.  866.3172  Qualitative hepatitis B virus antigen assays.

    (a) Identification. A qualitative hepatitis B virus (HBV) antigen 
assay is identified as an in vitro diagnostic device intended for 
prescription use for qualitative use with human serum, plasma, or other 
matrices that aids in the diagnosis of chronic or acute HBV infection. 
HBV surface antigen (HbsAg) is also used for screening of HBV infection 
in pregnant women to identify neonates who are at risk of acquiring 
hepatitis B during perinatal period. The assay is not intended for 
screening of blood, plasma, cells, or tissue donors.
    (b) Classification. Class II (special controls). The special 
controls for this device are:
    (1) The labeling required under Sec.  809.10(b) of this chapter 
must include:
    (i) A prominent statement that the assay is not intended for the 
screening of blood, plasma, cells, or tissue donors.
    (ii) A detailed explanation of the principles of operation and 
procedures for performing the assay.
    (iii) A detailed explanation of the interpretation of results.
    (iv) Limitations, which must be updated to reflect current clinical 
practice and disease presentation and management. The limitations must 
include statements that indicate:
    (A) The specimen types for which the device has been cleared, and 
that use of this assay with specimen types other than those 
specifically cleared for this device may result in inaccurate assay 
results.
    (B) When appropriate, performance characteristics of the assay have 
not been established in populations of immunocompromised or 
immunosuppressed patients or other populations where assay performance 
may be affected.
    (C) Diagnosis of hepatitis B infection should not be established on 
the basis of a single assay result but should be determined by a 
licensed healthcare professional in conjunction with the clinical 
presentation, history, and other diagnostic procedures.
    (D) Detection of HBV antigens indicates a current infection with 
hepatitis B virus but does not differentiate between acute or chronic 
infection. False reactive HbsAg result may occur for up to 2 weeks 
after vaccination with HbsAg containing vaccine.
    (E) Current methods for the detection of hepatitis B antigens may 
not detect all potentially infected individuals. A non-reactive assay 
result does not exclude the possibility of exposure to or infection 
with hepatitis B virus. A non-reactive assay result in individuals with 
prior exposure to hepatitis B may be due to but not limited to antigen 
levels below the detection limit of this assay or lack of antigen 
reactivity to the antibodies in this assay. HBV mutants lacking the 
ability to produce antigens have been reported. These may occur as 
``escape'' mutants in the presence of anti-HBV antibodies and such 
patients may be infectious.
    (F) Results obtained with this assay may not be used 
interchangeably with results obtained with a different manufacturer's 
assay.
    (2) Design verification and validation must include the following:
    (i) A detailed device description, including all parts that make up 
the device, ancillary reagents required but not provided, an 
explanation of the device methodology, design of the capture 
antibody(ies), external controls, and computational path from collected 
raw data to reported result (e.g., how collected raw signals are 
converted into a reported signal and result), as applicable to the 
detection method and device design.

[[Page 44976]]

    (ii) For devices with assay calibrators, the design and composition 
of all primary, secondary, and subsequent quantitation standards used 
for calibration as well as their traceability to a standardized 
reference material that FDA has determined is appropriate (e.g., a 
recognized consensus standard). In addition, analytical testing must be 
performed following the release of a new lot of the standard material 
that was used for device clearance or approval, or when there is a 
transition to a new calibration standard.
    (iii) Documentation and characterization (e.g., supplier, 
determination of identity, purity, and stability) of all critical 
reagents (including description of the capture antibody(ies)), and 
protocols for maintaining product integrity throughout its labeled 
shelf life.
    (iv) Risk analysis and management strategies, such as Failure Modes 
Effects Analysis and/or Hazard Analysis and Critical Control Points 
summaries and their impact on assay performance.
    (v) Final release criteria to be used for manufactured assay lots 
with appropriate evidence that lots released at the extremes of the 
specifications will meet the identified analytical and clinical 
performance characteristics as well as stability.
    (vi) Stability studies for reagents must include documentation of 
an assessment of real-time stability for multiple reagent lots using 
the indicated specimen types and must use acceptance criteria that 
ensure that analytical and clinical performance characteristics are met 
when stability is assigned based on the extremes of the acceptance 
range.
    (vii) All stability protocols, including acceptance criteria.
    (viii) Final release assay results for each lot used in clinical 
studies.
    (ix) Reproducibility study data that includes the testing of three 
independent production lots.
    (x) Detailed documentation of analytical performance studies 
conducted, as appropriate to the technology, specimen types tested, and 
intended use of the device, including, the limit of blank (LoB), limit 
of detection (LoD), cutoff, precision (reproducibility) including lot-
to-lot and/or instrument-to-instrument precision, interference, cross 
reactivity, carryover, hook effect, seroconversion panel testing, 
matrix equivalency, prominent mutants/variants detection (e.g., for 
HbsAg), specimen stability, reagent stability, and cross-genotype 
antigen detection sensitivity, when appropriate.
    (xi) Analytical sensitivity of the assay that is the same or better 
than that of other cleared or approved assays.
    (xii) For devices with associated software or instrumentation, 
documentation must include a detailed description of device software, 
including software applications and hardware-based devices that 
incorporate software. The detailed description must include 
documentation of verification, validation, and hazard analysis and risk 
assessment activities, including an assessment of the impact of threats 
and vulnerabilities on device functionality and end users/patients as 
part of cybersecurity review.
    (xiii) Detailed documentation and results from a clinical study. 
Performance must be analyzed relative to an FDA cleared or approved HBV 
antigen assay or a comparator that FDA has determined is appropriate. 
This study must be conducted using appropriate patient samples, with an 
appropriate number of HBV reactive and non-reactive samples in 
applicable risk and disease categories, and any applicable confirmatory 
testing. Additional relevant patient groups must be validated as 
appropriate. The samples must include prospective (sequential) samples 
for each identified specimen type and, as appropriate, additional 
characterized clinical samples. Samples must be sourced from 
geographically diverse areas. This study must be conducted in the 
appropriate settings by the intended users to demonstrate clinical 
performance.

0
3. Add Sec.  866.3173 to subpart D to read as follows:


Sec.  866.3173  Hepatitis B virus antibody assays.

    (a) Identification. A hepatitis B virus (HBV) antibody assay is 
identified as an in vitro diagnostic device intended for prescription 
use in the detection of antibodies to HBV in human serum, plasma, or 
other matrices, and as a device that aids in the diagnosis of HBV 
infection in persons with signs and symptoms of hepatitis and in 
persons at risk for hepatitis B infection. Results from assays may be 
qualitative or quantitative, such as quantitative anti-HBs. In 
addition, results from an anti-HBc IgM (IgM antibodies to core antigen) 
assay indicating the presence of anti-HBc IgM are indicative of recent 
HBV infection. Anti-HBs (antibodies to surface antigen) assay results 
may be used as an aid in the determination of susceptibility to HBV 
infection in individuals prior to or following HBV vaccination or when 
vaccination status is unknown. The assay is not intended for screening 
of blood, plasma, cells, or tissue donors. The assay is intended as an 
aid in diagnosis in conjunction with clinical findings and other 
diagnostic procedures.
    (b) Classification. Class II (special controls). The special 
controls for this device are:
    (1) The labeling required under Sec.  809.10(b) of this chapter 
must include:
    (i) A prominent statement that the assay is not intended for the 
screening of blood, plasma, cells, or tissue donors.
    (ii) A detailed explanation of the principles of operation and 
procedures for performing the assay.
    (iii) A detailed explanation of the interpretation of results.
    (iv) Limitations, which must be updated to reflect current clinical 
practice and disease presentation and management. The limitations must 
include statements that indicate:
    (A) When appropriate, performance characteristics of the assay have 
not been established in populations of immunocompromised or 
immunosuppressed patients or other special populations where assay 
performance may be affected.
    (B) Detection of HBV antibodies to a single viral antigen indicates 
a present or past infection with hepatitis B virus, but does not 
differentiate between acute, chronic, or resolved infection.
    (C) The specimen types for which the device has been cleared, and 
that use of the assay with specimen types other than those specifically 
cleared for this device may result in inaccurate assay results.
    (D) Diagnosis of hepatitis B infection should not be established on 
the basis of a single assay result but should be determined by a 
licensed healthcare professional in conjunction with the clinical 
presentation, history, and other diagnostic procedures.
    (E) A non-reactive assay result may occur early during acute 
infection, prior to development of a host antibody response to 
infection, or when analyte levels are below the limit of detection of 
the assay.
    (F) Results obtained with this assay may not be used 
interchangeably with results obtained with a different manufacturer's 
assay.
    (v) For devices intended for the quantitative detection of HBV 
antibodies (anti-HBs), in addition to the special controls listed in 
paragraphs (b)(1) and (2) of this section, labeling required under 
Sec.  809.10(b) of this chapter must include:
    (A) The assay calibrators' traceability to a standardized reference 
material that FDA has determined is appropriate (e.g., a recognized 
consensus standard) and the limit of blank (LoB), limit of

[[Page 44977]]

detection (LoD), limit of quantitation (LoQ), linearity, and precision 
to define the analytical measuring interval.
    (B) Performance results of the analytical sensitivity study testing 
a standardized reference material that FDA has determined is 
appropriate (e.g., a recognized consensus standard).
    (2) Design verification and validation must include the following:
    (i) Detailed device description, including all parts that make up 
the device, ancillary reagents required but not provided, an 
explanation of the device methodology, and design of the antigen(s) and 
capture antibody(ies) sequences, rationale for the selected epitope(s), 
degree of amino acid sequence conservation of the target, and the 
design and composition of all primary, secondary and subsequent 
standards used for calibration.
    (ii) Documentation and characterization (e.g., supplier, 
determination of identity, and stability) of all critical reagents 
(including description of the antigen(s) and capture antibody(ies)), 
and protocols for maintaining product integrity throughout its labeled 
shelf life.
    (iii) Risk analysis and management strategies, such as Failure 
Modes Effects Analysis and/or Hazard Analysis and Critical Control 
Points summaries and their impact on assay performance.
    (iv) Final release criteria to be used for manufactured assay lots 
with appropriate evidence that lots released at the extremes of the 
specifications will meet the identified analytical and clinical 
performance characteristics as well as stability.
    (v) Stability studies for reagents must include documentation of an 
assessment of real-time stability for multiple reagent lots using the 
indicated specimen types and must use acceptance criteria that ensure 
that analytical and clinical performance characteristics are met when 
stability is assigned based on the extremes of the acceptance range.
    (vi) All stability protocols, including acceptance criteria.
    (vii) When applicable, analytical sensitivity of the assay that is 
the same or better than that of other cleared or approved assays.
    (viii) Analytical performance studies and results for determining 
the limit of blank (LoB), limit of detection (LoD), cutoff, precision 
(reproducibility), including lot-to-lot and/or instrument-to-instrument 
precision, interference, cross reactivity, carryover, hook effect, 
seroconversion panel testing, matrix equivalency, specimen stability, 
reagent stability, and cross-genotype antibody detection sensitivity, 
when appropriate.
    (ix) For devices intended for the detection of antibodies for which 
a standardized reference material (that FDA has determined is 
appropriate) is available, the analytical sensitivity study and results 
testing the standardized reference material. Detailed documentation of 
that study and its results must be provided, including the study 
protocol, study report, testing results, and all statistical analyses.
    (x) For devices with associated software or instrumentation, 
documentation must include a detailed description of device software, 
including software applications and hardware-based devices that 
incorporate software. The detailed description must include 
documentation of verification, validation, and hazard analysis and risk 
assessment activities, including an assessment of the impact of threats 
and vulnerabilities on device functionality and end users/patients as 
part of cybersecurity review.
    (xi) Detailed documentation of clinical performance testing from a 
clinical study with an appropriate number of HBV reactive and non-
reactive samples in applicable risk categories and conducted in the 
appropriate settings by the intended users. Performance must be 
analyzed relative to an FDA cleared or approved HBV antibody assay or a 
comparator that FDA has determined is appropriate. Additional relevant 
patient groups must be validated as appropriate. The samples must 
include prospective (sequential) samples for each identified specimen 
type and, as appropriate, additional characterized clinical samples. 
Samples must be sourced from geographically diverse areas.
    (3) For any HBV antibody assay intended for quantitative detection 
of anti-HBV antibodies, the following special controls, in addition to 
those special controls listed in paragraphs (b)(1) and (2) of this 
section, also apply:
    (i) Detailed documentation of the metrological calibration 
traceability hierarchy to a standardized reference material that FDA 
has determined is appropriate.
    (ii) Detailed documentation of the following analytical performance 
studies conducted, as appropriate to the technology, specimen types 
tested, and intended use of the device, including upper and lower 
limits of quantitation (UloQ and LloQ, respectively), linearity using 
clinical samples, and an accuracy study using the recognized 
international standard material.

0
4. Add Sec.  866.3174 to subpart D to read as follows:


Sec.  866.3174  Hepatitis B virus nucleic acid-based assays.

    (a) Identification. A nucleic acid-based hepatitis B virus (HBV) 
assay is identified as an in vitro diagnostic device intended for 
prescription use in the detection of HBV nucleic acid in specimens from 
individuals with antibody evidence of HBV infection. In these devices, 
the detection of HBV nucleic acid is used as an aid in the management 
of HBV-infected individuals. The assay is intended for use with human 
serum or plasma (and other matrices as applicable) from individuals 
with HBV. The assay is not intended for use as a donor screening assay 
for the presence of HBV nucleic acids in blood, blood products, plasma, 
cells, or tissue donors, or as a diagnostic assay to confirm the 
presence of HBV infection.
    (b) Classification. Class II (special controls). The special 
controls for this device are:
    (1) Labeling required under Sec.  809.10(b) of this chapter must 
include:
    (i) A prominent statement that the assay is not intended for use as 
a screening assay for the presence of HBV DNA in blood or blood 
products, plasma, cells, or tissue donors, or as a diagnostic assay to 
confirm the presence of HBV infection.
    (ii) A detailed explanation of the principles of operation and 
procedures for performing the assay.
    (iii) A detailed explanation of the interpretation of results.
    (iv) Limitations, which must be updated to reflect current clinical 
practice and disease presentation and/or management. These limitations 
must include statements that indicate:
    (A) Management of patients undergoing HBV treatment should not be 
established on the basis of a single assay result but should be 
determined by a licensed healthcare professional in conjunction with 
the clinical presentation, history, and other diagnostic procedures, 
e.g., HBV serologic testing, liver function assays, liver elastography, 
etc.
    (B) The specimen types for which the device has been cleared, and 
that use of this assay with specimen types other than those 
specifically cleared for this device may result in inaccurate assay 
results.
    (C) The results obtained with this assay may not be used 
interchangeably with results obtained with a different manufacturer's 
assay.
    (2) Design verification and validation must include the following:
    (i) Detailed device description, including the device components, 
ancillary reagents required but not

[[Page 44978]]

provided, and an explanation of the device methodology. Additional 
information appropriate to the technology must be included such as 
design of primers and probes, rationale for the selected gene targets, 
specifications for amplicon size, and degree of nucleic acid sequence 
conservation.
    (ii) For devices with assay calibrators, the design and composition 
of all primary, secondary, and subsequent quantitation standards used 
for calibration as well as their traceability to a standardized 
reference material that FDA has determined is appropriate (e.g., a 
recognized consensus standard). In addition, analytical testing must be 
performed following the release of a new lot of the standard material 
that was used for device clearance or approval, or when there is a 
transition to a new calibration standard.
    (iii) Documentation and characterization (e.g., determination of 
the identity, supplier, purity, and stability) of all critical reagents 
(including nucleic acid sequences for primers and probes) and protocols 
for maintaining product integrity.
    (iv) Risk analysis and management strategies demonstrating how risk 
control measures are implemented to address device system hazards, such 
as Failure Modes Effects Analysis and/or Hazard Analysis and Critical 
Control Points summaries and their impact on assay performance.
    (v) Final release criteria to be used for manufactured assay lots 
with appropriate evidence that lots released at the extremes of the 
specification will meet the identified analytical and clinical 
performance characteristics as well as stability.
    (vi) Stability studies for reagents must include documentation of 
an assessment of real-time stability for multiple reagent lots using 
the indicated specimen types and must use acceptance criteria that 
ensure that analytical and clinical performance characteristics are met 
when stability is assigned based on the extremes of the acceptance 
range.
    (vii) All stability protocols, including acceptance criteria.
    (viii) Detailed documentation of analytical performance studies 
conducted as appropriate to the technology, specimen types tested, and 
intended use of the device, including limit of detection (LoD), 
linearity, precision, endogenous and exogenous interferences, cross-
reactivity, carryover, matrix equivalency, sample and reagents 
stability, and as applicable, upper and lower limits of quantitation 
(ULoQ and LLoQ, respectively). Samples selected for use must be from 
subjects with clinically relevant circulating genotypes in the United 
States. Cross-reactivity studies must include samples from HBV nucleic 
acid negative subjects with other viral or non-viral causes of liver 
disease, including autoimmune hepatitis, alcoholic liver disease, 
chronic hepatitis C virus, primary biliary cirrhosis, and nonalcoholic 
steatohepatitis, when applicable. The effect of each identified 
nucleic-acid isolation and purification procedure on detection must be 
evaluated.
    (ix) Analytical sensitivity of the assay that is the same or better 
than that of other cleared or approved assays.
    (x) For devices with associated software or instrumentation, 
documentation must include a detailed description of device software, 
including software applications and hardware-based devices that 
incorporate software. The detailed description must include 
documentation of verification, validation, and hazard analysis and risk 
assessment activities, including an assessment of the impact of threats 
and vulnerabilities on device functionality and end users/patients as 
part of cybersecurity review.
    (xi) Detailed documentation of performance from a clinical study 
with a design and number of clinical samples (appropriately 
statistically powered) that is appropriate for the intended use of the 
device as well as conducted in the appropriate settings by the intended 
users. The samples must include prospective (sequential) samples for 
each claimed specimen type and, as appropriate, additional 
characterized clinical samples. Samples must be sourced from 
geographically diverse areas.

Grace R. Graham,
Deputy Commissioner for Policy, Legislation, and International Affairs.
[FR Doc. 2025-18082 Filed 9-17-25; 8:45 am]
BILLING CODE 4164-01-P