Culture, Yeast with Direct Fluorescent KOH and Limited Susceptibility

Test Code

36270

CPT Codes
87102, 87206

Includes

If culture is positive, then Identification and Susceptibility will be performed at an additional charge (CPT code(s): 87106, 87186)

Preferred Specimen

Oral or vaginal swab collected in Amies Liquid Transport Swab, Amies Gel Transport Swab, Amies Liquid Elution Swab (ESwab) or equivalent

Minimum Volume

One swab specimen in transport medium • 5 mL unpreserved urine

Other Acceptable Specimens

10 mL unpreserved urine collected in a plastic, sterile, leak-proof container • Rectal mucosa swab (without feces)

Instructions

For surveillance testing - Composite skin of axilla/groin, or nasal swab specimen

Transport Container

ESwab, Liquid Amies (red-cap), or gel Amies (blue-cap)
Urine: Sterile, leak-proof container

Transport Temperature

Preserved swab specimen: Room temperature
Unpreserved urine: Refrigerated (cold packs)

Specimen Stability

Preserved swab specimens
Room temperature: 72 hours
Refrigerated: 72 hours
Frozen: Unacceptable

Unpreserved urine
Room temperature: Unacceptable
Refrigerated: 48 hours
Frozen: Unacceptable

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Stool • Sputum • Blood • Bone marrow • Hair • Nails • Specimen received frozen • Specimen in formalin • Serum • Body fluid • Preserved urine • Tissue

Methodology
Culture with Phenotypic Microscopic Evaluation, Fluorescent Microscopy • Matrix Assisted Laser Desorption Ionization-Time of Flight

Susceptibility testing is only performed when appropriate using Minimum Inhibitory Concentration (MIC)

Reference Range

See Laboratory Report

Clinical Significance

This test is used to identify a clinically significant yeast and determine its susceptibility to a limited set of antifungal agents. Potassium hydroxide (KOH), which dissolves human cells, helps detect the presence of fungus. This test may be helpful in optimizing treatment for recurrent yeast infections.

The susceptibility of a yeast isolate is measured by determining the minimum inhibitory concentration (MIC), which is the lowest drug concentration that prevents growth. An isolate can be categorized as susceptible, intermediate, susceptible-dose dependent, or resistant by comparing the MIC of an isolate to established clinical breakpoints [1]. MIC interpretations are based on recently published guidelines from the Clinical and Laboratory Standards Institute (CLSI). When a clinical breakpoint for an antifungal agent is not established by CLSI guidelines, only the MIC value is reported. For additional guidance, please review current CLSI documents related to antifungal susceptibility testing of yeasts.

Because treatment outcomes are influenced by many factors (eg, drug pharmacokinetics, pharmacodynamics, and interactions; the patient's immune response; disease severity), a "susceptible" or a "resistant" result does not ensure that a patient will or will not respond to a particular drug.

Invasive yeast infections, commonly caused by Candida and Cryptococcus, are associated with significant morbidity and mortality especially in immunocompromised individuals [2,3]. Species of these organisms have unique virulence and antifungal susceptibility. A particular species can be resistant to some antifungal agents and susceptible to others. Therefore, species identification and antifungal susceptibility testing can help guide treatment decisions for invasive infections [4]. Yeast susceptibility testing is useful when a yeast's identity does not reliably predict its susceptibility, particularly when the identified yeast belongs to a species known to resist common antifungal agents [1].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. CLSI. Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts. 4th ed. CLSI guideline M27. Clinical and Laboratory Standards Institute; 2017.
2. Invasive candidiasis statistics. Centers for Disease Control and Prevention. Updated August 24, 2021. Accessed February 7, 2022. https://www.cdc.gov/fungal/diseases/candidiasis/invasive/statistics.html
3. C. neoformans Infection Statistics. Centers for Disease Control and Prevention. Updated May 26, 2020. Accessed February 7, 2022. https://www.cdc.gov/fungal/diseases/cryptococcosis-neoformans/statistics.html
4. Pappas PG, et al. Clin Infect Dis. 2016;62(4):e1-e50.

Performing Laboratory

Quest Diagnostics - West Region

Last Updated: November 6, 2024

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.