---
kind: "section"
citation: "21 U.S.C. § 360a–2"
title: "21"
title_heading: "Food and Drugs"
number: "360a–2"
heading: "Susceptibility test interpretive criteria for microorganisms"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/21/360a-2"
units:
  - "Chapter 9 — Federal Food, Drug, and Cosmetic Act"
  - "Subchapter V — Drugs and Devices"
  - "Part A — Drugs and Devices"
---

# §360a–2. Susceptibility test interpretive criteria for microorganisms

- (a) **Purpose; identification of criteria—**
  - (1) **Purpose—** The purpose of this section is to clarify the [Secretary](/usc/21/321.md?p=d)’s authority to—
    - (A) efficiently update susceptibility test interpretive criteria for antimicrobial [drugs](/usc/21/321.md?p=g-1) when necessary for public health, due to, among other things, the constant evolution of microorganisms that leads to the development of resistance to [drugs](/usc/21/321.md?p=g-1) that have been effective in decreasing morbidity and mortality for patients, which warrants unique management of antimicrobial [drugs](/usc/21/321.md?p=g-1) that is inappropriate for most other [drugs](/usc/21/321.md?p=g-1) in order to delay or prevent the development of further resistance to existing therapies;
    - (B) provide for public notice of the availability of recognized interpretive criteria and interpretive criteria standards; and
    - (C) clear under [section 360(k) of this title](/usc/21/360.md?p=k), classify under [section 360c(f)(2) of this title](/usc/21/360c.md?p=f-2), or approve under [section 360e of this title](/usc/21/360e.md), antimicrobial susceptibility testing [devices](/usc/21/321.md?p=h-1) utilizing updated, recognized susceptibility test interpretive criteria to characterize the in vitro susceptibility of particular bacteria, fungi, or other microorganisms, as applicable, to antimicrobial [drugs](/usc/21/321.md?p=g-1).
  - (2) **Identification of criteria—** The [Secretary](/usc/21/321.md?p=d) shall identify appropriate susceptibility test interpretive criteria with respect to antimicrobial [drugs](/usc/21/321.md?p=g-1)—
    - (A) if such criteria are available on the date of approval of the [drug](/usc/21/321.md?p=g-1) under [section 355 of this title](/usc/21/355.md) or licensure of the [drug](/usc/21/321.md?p=g-1) under [section 262 of title 42](/usc/42/262.md) (as applicable), upon such approval or licensure; or
    - (B) if such criteria are unavailable on such date, on the date on which such criteria are available for such [drug](/usc/21/321.md?p=g-1).
  - (3) **Bases for initial identification—** The [Secretary](/usc/21/321.md?p=d) shall identify appropriate susceptibility test interpretive criteria under [paragraph (2)](#a-2), based on the [Secretary](/usc/21/321.md?p=d)’s review of, to the extent available and relevant—
    - (A) preclinical and clinical data, including pharmacokinetic, pharmacodynamic, and epidemiological data;
    - (B) the relationship of susceptibility test interpretive criteria to morbidity and mortality associated with the disease or condition for which such [drug](/usc/21/321.md?p=g-1) is used; and
    - (C) such other evidence and information as the [Secretary](/usc/21/321.md?p=d) considers appropriate.
- (b) **Susceptibility test Interpretive Criteria Website—**
  - (1) **In general—** Not later than 1 year after December 13, 2016, the [Secretary](/usc/21/321.md?p=d) shall establish, and maintain thereafter, on the website of the [Food](/usc/21/321.md?p=f) and [Drug](/usc/21/321.md?p=g-1) Administration, a dedicated website that contains a list of any appropriate new or updated susceptibility test interpretive criteria standards and interpretive criteria in accordance with [paragraph (2)](#b-2) (referred to in this section as the “Interpretive Criteria Website”).
  - (2) **Listing of susceptibility test interpretive criteria standards and interpretive criteria—**
    - (A) **In general—** The list described in [paragraph (1)](#b-1) shall consist of any new or updated susceptibility test interpretive criteria standards that are—
      - (i) established by a nationally or internationally recognized standard development organization that—
        - (I) establishes and maintains procedures to address potential conflicts of interest and ensure transparent decisionmaking;
        - (II) holds open meetings to ensure that there is an opportunity for public input by interested parties, and establishes and maintains processes to ensure that such input is considered in decisionmaking; and
        - (III) permits its standards to be made publicly available, through the National Library of Medicine or another similar source acceptable to the [Secretary](/usc/21/321.md?p=d); and
      - (ii) recognized in whole, or in part, by the [Secretary](/usc/21/321.md?p=d) under [subsection (c)](#c).
    - (B) **Other list—** The Interpretive Criteria Website shall, in addition to the list described in [subparagraph (A)](#b-2-A), include a list of interpretive criteria, if any, that the [Secretary](/usc/21/321.md?p=d) has determined to be appropriate with respect to legally marketed antimicrobial [drugs](/usc/21/321.md?p=g-1), where—
      - (i) the [Secretary](/usc/21/321.md?p=d) does not recognize, in whole or in part, an interpretive criteria standard described under [subparagraph (A)](#b-2-A) otherwise applicable to such a [drug](/usc/21/321.md?p=g-1);
      - (ii) the [Secretary](/usc/21/321.md?p=d) withdraws under [subsection (c)(1)(A)](#c-1-A) recognition of a standard, in whole or in part, otherwise applicable to such a [drug](/usc/21/321.md?p=g-1);
      - (iii) the [Secretary](/usc/21/321.md?p=d) approves an application under [section 355 of this title](/usc/21/355.md) or [section 262 of title 42](/usc/42/262.md), as applicable, with respect to marketing of such a [drug](/usc/21/321.md?p=g-1) for which there are no relevant interpretive criteria included in a standard recognized by the [Secretary](/usc/21/321.md?p=d) under [subsection (c)](#c); or
      - (iv) because the characteristics of such a [drug](/usc/21/321.md?p=g-1) differ from other [drugs](/usc/21/321.md?p=g-1) with the same active ingredient, the interpretive criteria with respect to such [drug](/usc/21/321.md?p=g-1)—
        - (I) differ from otherwise applicable interpretive criteria included in a standard listed under [subparagraph (A)](#b-2-A) or interpretive criteria otherwise listed under this subparagraph; and
        - (II) are determined by the [Secretary](/usc/21/321.md?p=d) to be appropriate for the [drug](/usc/21/321.md?p=g-1).
    - (C) **Required statements—** The Interpretive Criteria Website shall include statements conveying—
      - (i) that the website provides information about the in vitro susceptibility of bacteria, fungi, or other microorganisms, as applicable to a certain [drug](/usc/21/321.md?p=g-1) (or [drugs](/usc/21/321.md?p=g-1));
      - (ii) that—
        - (I) the safety and efficacy of such [drugs](/usc/21/321.md?p=g-1) in treating clinical infections due to such bacteria, fungi, or other microorganisms, as applicable, may or may not have been established in adequate and well-controlled clinical trials in order for the susceptibility information described in [clause (i)](#b-2-C-i) to be included on the website; and
        - (II) the clinical significance of such susceptibility information in such instances is unknown;
      - (iii) that the approved [product](/usc/21/360eee.md?p=13) [labeling](/usc/21/321.md?p=m) for specific [drugs](/usc/21/321.md?p=g-1) provides the uses for which the [Secretary](/usc/21/321.md?p=d) has approved the [product](/usc/21/360eee.md?p=13); and
      - (iv) any other information that the [Secretary](/usc/21/321.md?p=d) determines appropriate to adequately convey the meaning of the data supporting the recognition or listing of susceptibility test interpretive criteria standards or susceptibility test interpretive criteria included on the website.
  - (3) **Notice—** Not later than the date on which the Interpretive Criteria Website is established, the [Secretary](/usc/21/321.md?p=d) shall publish a notice of that establishment in the Federal Register.
  - (4) **Inapplicability of misbranding provision—** The inclusion in the approved [labeling](/usc/21/321.md?p=m) of an antimicrobial [drug](/usc/21/321.md?p=g-1) of a reference or hyperlink to the Interpretive Criteria Website, in and of itself, shall not cause the [drug](/usc/21/321.md?p=g-1) to be misbranded in violation of [section 352 of this title](/usc/21/352.md).
  - (5) **Trade secrets and confidential information—** Nothing in this section shall be construed as authorizing the [Secretary](/usc/21/321.md?p=d) to disclose any information that is a trade secret or confidential information subject to [section 552(b)(4) of title 5](/usc/5/552.md?p=b-4).
- (c) **Recognition of susceptibility test interpretive criteria—**
  - (1) **Evaluation and publication—**
    - (A) **In general—** Beginning on the date of the establishment of the Interpretive Criteria Website, and at least every 6 months thereafter, the [Secretary](/usc/21/321.md?p=d) shall—
      - (i) evaluate any appropriate new or updated susceptibility test interpretive criteria standards established by a nationally or internationally recognized standard development organization described in [subsection (b)(2)(A)(i)](#b-2-A-i); and
      - (ii) publish on the public website of the [Food](/usc/21/321.md?p=f) and [Drug](/usc/21/321.md?p=g-1) Administration a notice—
        - (I) withdrawing recognition of any different susceptibility test interpretive criteria standard, in whole or in part;
        - (II) recognizing the new or updated standards;
        - (III) recognizing one or more parts of the new or updated interpretive criteria specified in such a standard and declining to recognize the remainder of such standard; and
        - (IV) making any necessary updates to the lists under [subsection (b)(2)](#b-2).
    - (B) **Upon approval of a drug—** Upon the approval of an initial or supplemental application for an antimicrobial [drug](/usc/21/321.md?p=g-1) under [section 355 of this title](/usc/21/355.md) or [section 262 of title 42](/usc/42/262.md), as applicable, where such approval is based on susceptibility test interpretive criteria which differ from those contained in a standard recognized, or from those otherwise listed, by the [Secretary](/usc/21/321.md?p=d) pursuant to this subsection, or for which there are no relevant interpretive criteria standards recognized, or interpretive criteria otherwise listed, by the [Secretary](/usc/21/321.md?p=d) pursuant to this subsection, the [Secretary](/usc/21/321.md?p=d) shall update the lists under subparagraphs [(A)](#b-2-A) and [(B)](#b-2-B) of subsection (b)(2) to include the susceptibility test interpretive criteria upon which such approval was based.
  - (2) **Bases for updating interpretive criteria standards—** In evaluating new or updated susceptibility test interpretive criteria standards under [paragraph (1)(A)](#c-1-A), the [Secretary](/usc/21/321.md?p=d) may consider—
    - (A) the [Secretary](/usc/21/321.md?p=d)’s determination that such a standard is not applicable to a particular [drug](/usc/21/321.md?p=g-1) because the characteristics of the [drug](/usc/21/321.md?p=g-1) differ from other [drugs](/usc/21/321.md?p=g-1) with the same active ingredient;
    - (B) information provided by interested third parties, including public comment on the annual compilation of notices published under [paragraph (3)](#c-3);
    - (C) any bases used to identify susceptibility test interpretive criteria under [subsection (a)(2)](#a-2); and
    - (D) such other information or factors as the [Secretary](/usc/21/321.md?p=d) determines appropriate.
  - (3) **Annual compilation of notices—** Each year, the [Secretary](/usc/21/321.md?p=d) shall compile the notices published under [paragraph (1)(A)](#c-1-A) and publish such compilation in the Federal Register and provide for public comment. If the [Secretary](/usc/21/321.md?p=d) receives comments, the [Secretary](/usc/21/321.md?p=d) shall review such comments and, if the [Secretary](/usc/21/321.md?p=d) determines appropriate, update pursuant to this subsection susceptibility test interpretive criteria standards or criteria—
    - (A) recognized by the [Secretary](/usc/21/321.md?p=d) under this subsection; or
    - (B) otherwise listed on the Interpretive Criteria Website under [subsection (b)(2)](#b-2).
  - (4) **Relation to section 360d(c) of this title—** Any susceptibility test interpretive standard recognized under this subsection or any criteria otherwise listed under [subsection (b)(2)(B)](#b-2-B) shall be deemed to be recognized as a standard by the [Secretary](/usc/21/321.md?p=d) under [section 360d(c)(1) of this title](/usc/21/360d.md?p=c-1).
  - (5) **Voluntary use of interpretive criteria—** Nothing in this section prohibits a [person](/usc/21/321.md?p=e) from seeking approval or clearance of a [drug](/usc/21/321.md?p=g-1) or [device](/usc/21/321.md?p=h-1), or changes to the [drug](/usc/21/321.md?p=g-1) or the [device](/usc/21/321.md?p=h-1), on the basis of susceptibility test interpretive criteria which differ from those contained in a standard recognized, or from those otherwise listed, by the [Secretary](/usc/21/321.md?p=d) pursuant to [subsection (b)(2)](#b-2).
- (d) **Antimicrobial drug labeling—**
  - (1) **Drugs marketed prior to establishment of Interpretive Criteria Website—**
    - (A) **In general—** With respect to an antimicrobial [drug](/usc/21/321.md?p=g-1) lawfully introduced or delivered for introduction into [interstate commerce](/usc/21/321.md?p=b) for commercial [distribution](/usc/21/360eee.md?p=5) before the establishment of the Interpretive Criteria Website, a holder of an approved application under [section 355 of this title](/usc/21/355.md) or [section 262 of title 42](/usc/42/262.md), as applicable, for each such [drug](/usc/21/321.md?p=g-1), not later than 1 year after establishment of the Interpretive Criteria Website described in [subsection (b)(1)](#b-1), shall remove susceptibility test interpretive criteria, if any, and related information from the approved [drug](/usc/21/321.md?p=g-1) [labeling](/usc/21/321.md?p=m) and replace it with a reference to the Interpretive Criteria Website.
    - (B) **Labeling changes—** The [labeling](/usc/21/321.md?p=m) changes required by this section shall be considered a minor change under section 314.70 of title 21, Code of Federal Regulations (or any successor regulations) that may be implemented through documentation in the next applicable annual report.
  - (2) **Drugs marketed subsequent to establishment of Interpretive Criteria Website—** With respect to antimicrobial [drugs](/usc/21/321.md?p=g-1) approved on or after the date of the establishment of the Interpretive Criteria Website described in [subsection (b)(1)](#b-1), the [labeling](/usc/21/321.md?p=m) for such a [drug](/usc/21/321.md?p=g-1) shall include, in lieu of susceptibility test interpretive criteria and related information, a reference to such Website.
- (e) **Special condition for marketing of antimicrobial susceptibility testing devices—**
  - (1) **In general—** Notwithstanding sections [351](/usc/21/351.md), [352](/usc/21/352.md), [355](/usc/21/355.md), [360](/usc/21/360.md), [360c](/usc/21/360c.md), and [360e](/usc/21/360e.md) of this title, if the conditions specified in [paragraph (2)](#e-2) are met (in addition to other applicable provisions under this subchapter) with respect to an antimicrobial susceptibility testing [device](/usc/21/321.md?p=h-1) described in [subsection (f)(1)](#f-1), the [Secretary](/usc/21/321.md?p=d) may authorize the marketing of such [device](/usc/21/321.md?p=h-1) for a use described in such subsection.
  - (2) **Conditions applicable to antimicrobial susceptibility testing devices—** The conditions specified in this paragraph are the following:
    - (A) The [device](/usc/21/321.md?p=h-1) is used to make a determination of susceptibility using susceptibility test interpretive criteria that are—
      - (i) included in a standard recognized by the [Secretary](/usc/21/321.md?p=d) under [subsection (c)](#c); or
      - (ii) otherwise listed on the Interpretive Criteria Website under [subsection (b)(2)](#b-2).
    - (B) The [labeling](/usc/21/321.md?p=m) of such [device](/usc/21/321.md?p=h-1) includes statements conveying—
      - (i) that the [device](/usc/21/321.md?p=h-1) provides information about the in vitro susceptibility of bacteria, fungi, or other microorganisms, as applicable to antimicrobial [drugs](/usc/21/321.md?p=g-1);
      - (ii) that—
        - (I) the safety and efficacy of such [drugs](/usc/21/321.md?p=g-1) in treating clinical infections due to such bacteria, fungi, or other microorganisms, as applicable, may or may not have been established in adequate and well-controlled clinical trials in order for the [device](/usc/21/321.md?p=h-1) to report the susceptibility of such bacteria, fungi, or other microorganisms, as applicable, to such [drugs](/usc/21/321.md?p=g-1); and
        - (II) the clinical significance of such susceptibility information in those instances is unknown;
      - (iii) that the approved [labeling](/usc/21/321.md?p=m) for [drugs](/usc/21/321.md?p=g-1) tested using such a [device](/usc/21/321.md?p=h-1) provides the uses for which the [Secretary](/usc/21/321.md?p=d) has approved such [drugs](/usc/21/321.md?p=g-1); and
      - (iv) any other information the [Secretary](/usc/21/321.md?p=d) determines appropriate to adequately convey the meaning of the data supporting the recognition or listing of susceptibility test interpretive criteria standards or susceptibility test interpretive criteria described in [subparagraph (A)](#e-2-A).
    - (C) The antimicrobial susceptibility testing [device](/usc/21/321.md?p=h-1) meets all other requirements to be cleared under [section 360(k) of this title](/usc/21/360.md?p=k), classified under [section 360c(f)(2) of this title](/usc/21/360c.md?p=f-2), or approved under [section 360e of this title](/usc/21/360e.md).
- (f) **Definitions—** In this section:
  - (1) The term “antimicrobial susceptibility testing [device](/usc/21/321.md?p=h-1)” means a [device](/usc/21/321.md?p=h-1) that utilizes susceptibility test interpretive criteria to determine and report the in vitro susceptibility of certain microorganisms to a [drug](/usc/21/321.md?p=g-1) (or [drugs](/usc/21/321.md?p=g-1)).
  - (2) The term “qualified infectious disease [product](/usc/21/360eee.md?p=13)” means a qualified infectious disease [product](/usc/21/360eee.md?p=13) designated under [section 355f(d) of this title](/usc/21/355f.md?p=d).
  - (3) The term “susceptibility test interpretive criteria” means—
    - (A) one or more specific numerical values which characterize the susceptibility of bacteria or other microorganisms to the [drug](/usc/21/321.md?p=g-1) tested; and
    - (B) related categorizations of such susceptibility, including categorization of the [drug](/usc/21/321.md?p=g-1) as susceptible, intermediate, resistant, or such other term as the [Secretary](/usc/21/321.md?p=d) determines appropriate.
  - (4)
    - (A) The term “antimicrobial [drug](/usc/21/321.md?p=g-1)” means, subject to [subparagraph (B)](#f-4-B), a systemic antibacterial or antifungal [drug](/usc/21/321.md?p=g-1) that—
      - (i) is intended for human use in the treatment of a disease or condition caused by a bacterium or fungus;
      - (ii) may include a qualified infectious disease [product](/usc/21/360eee.md?p=13) designated under [section 355f(d) of this title](/usc/21/355f.md?p=d); and
      - (iii) is subject to [section 353(b)(1) of this title](/usc/21/353.md?p=b-1).
    - (B) If provided by the [Secretary](/usc/21/321.md?p=d) through regulations, such term may include—
      - (i) [drugs](/usc/21/321.md?p=g-1) other than systemic antibacterial and antifungal [drugs](/usc/21/321.md?p=g-1); and
      - (ii) biological [products](/usc/21/360eee.md?p=13) (as such term is defined in [section 262 of title 42](/usc/42/262.md)) to the extent such [products](/usc/21/360eee.md?p=13) exhibit antimicrobial activity.
  - (5) The term “interpretive criteria standard” means a compilation of susceptibility test interpretive criteria developed by a standard development organization that meets the criteria set forth in [subsection (b)(2)(A)(i)](#b-2-A-i).
- (g) **Rule of construction—** Nothing in this section shall be construed to—
  - (1) alter the standards of evidence under subsection (c) or (d) of [section 355 of this title](/usc/21/355.md) (including the substantial evidence standard under [section 355(d) of this title](/usc/21/355.md?p=d)) or under [section 262 of title 42](/usc/42/262.md) (as applicable); or
  - (2) with respect to clearing [devices](/usc/21/321.md?p=h-1) under [section 360(k) of this title](/usc/21/360.md?p=k), classifying [devices](/usc/21/321.md?p=h-1) under [section 360c(f)(2) of this title](/usc/21/360c.md?p=f-2), or approving [devices](/usc/21/321.md?p=h-1) under [section 360e of this title](/usc/21/360e.md)—
    - (A) apply with respect to any [drug](/usc/21/321.md?p=g-1), [device](/usc/21/321.md?p=h-1), or biological [product](/usc/21/360eee.md?p=13), in any context other than an antimicrobial [drug](/usc/21/321.md?p=g-1) and an antimicrobial susceptibility testing [device](/usc/21/321.md?p=h-1) that uses susceptibility test interpretive criteria to characterize and report the susceptibility of certain bacteria, fungi, or other microorganisms, as applicable, to such [drug](/usc/21/321.md?p=g-1) to reflect patient morbidity and mortality in accordance with this section; or
    - (B) unless specifically stated, have any effect on authorities provided under other sections of this chapter, including any regulations issued under such sections.

## Source credit

(June 25, 1938, ch. 675, § 511A, as added Pub. L. 114–255, div. A, title III, § 3044(a), Dec. 13, 2016, 130 Stat. 1114.)

## Notes

### Statutory Notes and Related Subsidiaries

### Construction

Nothing in this section to be construed to restrict the prescribing of antimicrobial drugs or other products, including drugs approved under section 356(h) of this title, by health care professionals, or to limit the practice of health care, see section 3043 of Pub. L. 114–255, set out as a Construction of 2016 Amendments note under section 356 of this title.

### Requests for Updates to Interpretive Criteria Website

Pub. L. 114–255, div. A, title III, § 3044(d), Dec. 13, 2016, 130 Stat. 1121, provided that: “Chapter 35 of title 44, United States Code, shall not apply to the collection of information from interested parties regarding updating the lists established under section 511A(b) of the Federal Food, Drug, and Cosmetic Act [21 U.S.C. 360a–2(b)] and posted on the Interpretive Criteria Website established under section 511A(c) [probably means section 511A(b)] of such Act.”