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Test ID: CLFAT Cryptococcus Antigen Titer, Lateral Flow Assay, Spinal Fluid

Useful For

Monitoring Cryptococcus antigen titers in cerebrospinal fluid

 

Aiding in the diagnosis of cryptococcosis

 

This test should not be used as a test of cure or to guide treatment decisions.

Reporting Name

Cryptococcus Ag Titer, LFA, CSF

Specimen Type

CSF


Specimen Required


Container/Tube: Sterile vial

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Refrigerated (preferred) 14 days
  Frozen  14 days

Clinical Information

Cryptococcosis is an invasive fungal infection caused by Cryptococcus neoformans or Cryptococcus gattii. Cryptococcus neoformans has been isolated from several sites in nature, particularly weathered pigeon droppings. C gatti was previously associated with tropical and subtropical regions only, however, more recently this organism has also been found to be endemic in British Columbia and among the Pacific Northwest United States and is associated with several different trees species.

 

Infection is usually acquired via the pulmonary route. Patients are often unaware of any exposure history. Approximately half of the patients with symptomatic disease have a predisposing immunosuppressive condition such as AIDS, steroid therapy, lymphoma, or sarcoidosis. Symptoms may include fever, headache, dizziness, ataxia, somnolence, and cough. While the majority of C neoformans infections occur in immunocompromised patient populations, C gattii is has a higher predilection for infection of healthy individuals.(1,2)

 

In addition to the lungs, cryptococcal infections frequently involve the central nervous system (CNS), particularly in patients infected with HIV. Mortality among patients with CNS cryptococcosis may approach 25% despite antibiotic therapy. Untreated CNS cryptococcosis is invariably fatal. Disseminated disease may affect any organ system and usually occurs in immunosuppressed individuals.

 

Note: According to the College of American Pathologists (CAP, IMM.41840), cerebrospinal fluid (CSF) samples submitted for initial diagnosis that test positive by the lateral flow assay should also be submitted for routine fungal culture. Fungal cultures are not required for CSF samples that are submitted to monitor Cryptococcus antigen titers during treatment.

Reference Values

Negative

Interpretation

The presence of cryptococcal antigen in any body fluid (serum or cerebrospinal fluid: CSF) is indicative of cryptococcosis.

 

Disseminated infection is usually accompanied by a positive serum test.

 

Declining titers may indicate regression of infection. However, monitoring titers to cryptococcal antigen should not be used as a test of cure or to guide treatment decisions. Low-level titers may persist for extended periods of time following appropriate therapy and resolution of infection.(3,4)

 

CSF specimens submitted for initial diagnosis that test positive by the lateral flow assay, should also be submitted for routine fungal culture. Culture can aid to differentiate between the 2 common Cryptococcus species causing disease (Cryptococcus neoformans and Cryptococcus gattii) and can be used for antifungal susceptibility testing, if necessary. CSF specimens submitted to monitor antigen levels during treatment do not need to be cultured.

Clinical Reference

1. Speed B, Dunt D: Clinical and host differences between infections with the two varieties of Cryptococcus neoformans. Clin Infect Dis. 1995;21(1):28-34

2. Chen S, Sorrell T, Nimmo G, et al: Epidemiology and host- and variety-dependent characteristics of infection due to Cryptococcus neoformans in Australia and New Zealand. Australasian Cyrptococcoal Study Group. Clin Infect Dis. 2000;31(2):499-505

3. Lu H, Zhou Y, Yin Y, et al: Cryptococcal antigen test revisited: significance for cryptococcal meningitis therapy monitoring in a tertiary Chinese hospital. J Clin Microbiol. 2005 June;43(6):2989-2990

4. Perfect JR, Dismukes WE, Dromer F, et al: Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin Infect Dis. 2010;50:291-322

5. Warren NG, Hazen KC: Candida, Cryptococcus, and other yeasts of medical importance. In: Marrya PR, ed. Manual of Clinical Microbiology. 7th ed. ASM Press; 1999: 1184-1199

6. Perfect JR: Cryptococcosis (Cryptococcus neoformans and Cryptococcus gattii). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:3146-3161

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 to 2 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87899

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CLFAT Cryptococcus Ag Titer, LFA, CSF 9817-8

 

Result ID Test Result Name Result LOINC Value
62076 Cryptococcus Ag Titer, LFA, CSF 9817-8

Method Name

Lateral Flow Assay (LFA)

Forms

If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.

Mayo Clinic Laboratories | Microbiology and Infectious Disease Catalog Additional Information:

mml-mbid-cnsinfections