Antifungal Susceptibility Test Interpretive Criteria

This web page provides information about the in vitro susceptibility of fungi to certain drugs.

The safety and efficacy of these drugs in treating clinical infections due to such fungi may not have been established in adequate and well-controlled clinical trials and the clinical significance of such susceptibility information in those instances is unknown.

The approved product labeling for specific drugs provides the uses for which the product is approved.

Labeling for these products can be found at Drugs@FDA or FDA Online Label Repository.

Recognized Standards

Performance Methods and Quality Control

FDA recognizes consensus standards for performance standards, methods standards, and quality control parameter standards including ranges for antimicrobial susceptibility testing.

Susceptibility Test Interpretive Criteria

The table below lists antifungal drugs and indicates which, if any, susceptibility test interpretive criteria, also known as “breakpoints” (abbreviated as STIC), are recognized or identified by FDA for that drug.

Unless specific exceptions and additions are identified in the table, FDA fully recognizes the standards published in:

• Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antifungal Susceptibility Testing of Yeasts. 3rd Ed. CLSI supplement M27M44S; 2022.
• Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antifungal Susceptibility Testing of Filamentous Fungi. 3rd Ed. CLSI supplement M38M51S; 2022.

FDA recognition of STIC standard(s) for a drug does not include recognition of epidemiological cutoff values (ECVs) for that drug.

FDA recognition of STIC standard(s) for a drug and fungal genus/species does include recognition of surrogate testing methods included in recognized standards for that drug and fungal genus/species.

Susceptibility Test Interpretive Criteria Recognized or Otherwise Identified by FDA

The hyperlinks included for certain antifungal drugs in the table below lead to information concerning:

• Exceptions or additions to the recognized standard of CLSI M27M44S and CLSI M38M51S

Drug	Route of Administration	STIC for Drug Included in CLSI Standards	Exceptions or Additions to CLSI Standards
Amphotericin B*	Injection	No	No
Anidulafungin	Injection	Yes	No
Caspofungin	Injection	Yes	No
Fluconazole	Injection, Oral	Yes	No
Flucytosine*	Oral	No	No
Griseofulvin*	Oral	No	No
Ibrexafungerp*	Oral	No	No
Isavuconazonium sulfate a	Injection, Oral	Yes b	No
Itraconazole	Oral	No	Yes
Ketoconazole*	Oral	No	No
Micafungin	Injection	Yes	No
Nystatin*	Oral	No	No
Oteseconazole*	Oral	No	No
Posaconazole*	Injection, Oral	No	No
Rezafungin	Injection	Yes	Yes
Terbinafine*	Oral	No	No
Voriconazole	Injection, oral	Yes	No

*No susceptibility test interpretive criteria are recognized by FDA for this drug at this time. 

^a Isavuconazonium sulfate is the prodrug of isavuconazole.

^b Breakpoints have been established and will be published in the next edition of M38M51S.