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Test ID: LFACX Cryptococcus Antigen with Reflex, Spinal Fluid

Useful For

Aiding in the diagnosis of cryptococcosis

 

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

 

This test should not be performed as a screening procedure for the general population.

Profile Information

Test ID Reporting Name Available Separately Always Performed
CLFA Cryptococcus Ag Screen w/Titer, CSF Yes Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CLFAT Cryptococcus Ag Titer, LFA, CSF Yes No
FGENC Fungal Culture, CSF Yes, (Order FGEN) No

Testing Algorithm

If result is positive, Cryptococcus antigen titer will be performed at an additional charge.

 

If Cryptococcus antigen titer is positive, then fungal culture will be performed at an additional charge.

Reporting Name

Cryptococcus Ag w/Reflex, LFA, CSF

Specimen Type

CSF


Specimen Required


Container/Tube: Sterile vial

Specimen Volume: 1 mL


Specimen Minimum Volume

0.5 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. C neoformans has been isolated from several sites in nature, particularly weathered pigeon droppings. C gattii was previously only associated with tropical and subtropical regions, 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 has a higher predilection for infection of healthy hosts.(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, which 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

CRYPTOCOCCUS ANTIGEN SCREEN WITH TITER

Negative

Reference values apply to all ages.

 

CRYPTOCOCCUS ANTIGEN TITER, LFA

Negative

Reference values apply to all ages.

 

FUNGAL CULTURE

Negative

If positive, fungus will be identified.

Reference values apply to all ages.

Interpretation

The presence of cryptococcal antigen in any body fluid (serum or cerebrospinal fluid: CSF) is indicative of cryptococcosis. Specimens that are positive by the lateral flow assay (LFA) screen are automatically repeated by the same method utilizing dilutions in order to generate a titer value. CSF specimens submitted for initial diagnosis, which test positive by LFA, 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.

 

Disseminated infection is usually accompanied by a positive serum test.

 

Higher Cryptococcus antigen titers appear to correlate with more severe infections. 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, as low level titers may persist for extended periods of time following appropriate therapy and the resolution of infection.

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. 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

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

5. 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

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 35 days

CPT Code Information

87899-Cryptococcus Ag Screen w/Titer, CSF

87899-Cryptococcus Ag Titer, LFA, CSF (as appropriate)

87102-Fungal Culture, CSF (as appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LFACX Cryptococcus Ag w/Reflex, LFA, CSF 29896-8

 

Result ID Test Result Name Result LOINC Value
62074 Cryptococcus Ag Screen w/Titer, CSF 29896-8

Method Name

Lateral Flow Assay (LFA)

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.

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:

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