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HelpTest 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, CSFSpecimen Type
CSFSpecimen Required
Container/Tube: Sterile vial
Specimen Volume: 1 mL
Collection Instructions: Submit specimen from collection vial 2 (preferred), 3, or 4.
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. More recently, however, this organism has been found to be endemic in British Columbia and the Pacific Northwestern United States and is associated with several different tree 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 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.
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 to generate a titer value. CSF specimens submitted for initial diagnosis that test positive by LFA should also be submitted for routine fungal culture. Culture can aid in differentiating 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 Cryptococcal Study Group. Clin Infect Dis. 2000 Aug;31(2):499-505. doi: 10.1086/313992
3. 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
4. Chang CC, Harrison TS, Bicanic TA, et al. Global guideline for the diagnosis and management of cryptococcosis: an initiative of the ECMM and ISHAM in cooperation with the ASM [published correction appears in Lancet Infect Dis. 2024;24(8):e485
5. Perfect JR, Bicanic T. Cryptococcosis diagnosis and treatment: What do we know now. Fungal Genet Biol. 2015;78:49-54. doi:10.1016/j.fgb.2014.10.003
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 35 daysCPT 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.
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