ARUP's Laboratory Test Directory

Antimicrobial Susceptibility - Yeast Susceptibility : 0060235

Mnemonic: MA YST

Methodology: Broth Microdilution
Performed: Sun-Sat
Reported: 2-5 days
Specimen Required: Collect: Actively growing isolate in pure culture.

Specimen Preparation: Transport sealed container with pure culture on agar slant. Place each specimen in individually sealed bag.

Storage/Transport Temperature: Room temperature.

Remarks: Isolate identification and specimen source required.

Unacceptable Conditions: Mixed cultures or non-viable organisms.

Stability (collection to initiation of testing): Ambient: 1 week; Refrigerated: 2 weeks; Frozen: Unacceptable

Reference Interval:
Effective May 16, 2011

Susceptible, intermediate, SDD (susceptible dose dependent), or resistant. Interpretive guidelines are provided only for Candida species.

MICs (minimum inhibitory concentrations) without interpretative guidelines are reported for yeast species other than Candida.

MECs (minimum effective concentration) are not reported for yeast species.
Interpretive Data: SDD = susceptibility is dose dependent.
NONE = Interpretive guidelines are not available

For amphotericin B, there are no CLSI breakpoints, but MIC greater than 1 is considered resistant.

For fluconazole the guidelines are based on experience with mucosal and invasive infections due to Candida species. When the isolate is C. glabrata and the MIC is less than or equal to 32 µg/mL the maximum dosage regimen should be used.

5-fluorocytosine
MIC breakpoints are based largely on historical data and partially on the drug's pharmacokinetics.

For itraconazole, the data are based entirely on experience with mucosal infections, and data supporting breakpoints for invasive infections due to Candida spp. are not available.

Voriconazole
MIC interpretation is used as surrogate for posaconazole interpretation.

SDD (susceptible dose dependent) applies to fluconazole, itraconazole, posaconazole, and voriconazole. Susceptibility is dependent on achieving the maximum possible level.

For anidulafungin, caspofungin, and micafungin, the data are based substantially on experience with non-neutropenic patients with candidemia. Clinical relevance in other settings is uncertain.

Susceptibility testing is performed by CLSI-approved broth microdilution method.
Note: The following agents will be tested: Amphotericin B, anidulafungin, caspofungin, fluconazole, 5-fluorocytosine, itraconazole, micafungin, posaconazole, and voriconazole. Candida species, Cryptococcus, Geotrichum and Trichosporon species are tested at ARUP.

If species identification is not provided, identification will be performed at ARUP for an additional charge.
CPT Code(s): 87186
Cross References: Yeast Susceptibility Panel (Antimicrobial Susceptibility - Yeast Susceptibility)