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Test ID: CCOC Coccidioides Antibody, Complement Fixation and Immunodiffusion, Spinal Fluid

Reporting Name

Coccidioides Ab, CompF/ImmDiff, CSF

Useful For

Diagnosing coccidioidomycosis using spinal fluid specimens

Specimen Type


Specimen Required

Container/Tube: Sterile vial

Specimen Volume: 2 mL

Collection Instructions: Submit specimen from collection vial 2.

Specimen Minimum Volume

1.2 mL

Specimen Stability Information

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

Reference Values



If positive, results are titered.




Results are reported as positive, negative, or equivocal.

Day(s) Performed

Monday through Friday

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

86635 x 3

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CCOC Coccidioides Ab, CompF/ImmDiff, CSF 88745-5


Result ID Test Result Name Result LOINC Value
81542 Coccidioides Ab, CompF, CSF 13917-0
21002 Coccidioides, IgG, ImmDiff, CSF 94662-4
21001 Coccidioides, IgM, ImmDiff, CSF 94663-2

Clinical Information

Coccidioidomycosis (valley fever, San Joaquin Valley fever) is a fungal infection found in the Southwestern United States, Central America, and South America. It is acquired by inhalation of arthroconidia of Coccidioides immitis/posadasii. Usually, it is a mild, self-limiting pulmonary infection. Less commonly, chronic pneumonia may occur, progressing to fibronodular cavitary disease. A rash often develops within 1 to 2 days, followed by erythema nodosum or multiforme and accompanying arthralgias. About 2 weeks after exposure, symptomatic patients develop fever, cough, malaise, and anorexia; chest pain is often severe. Coccidioidomycosis may disseminate beyond the lungs to involve multiple organs, including the meninges.


IgG antibody is detected by the complement-fixation tests. Precipitating antibodies (IgM and IgG) are detected by immunodiffusion. They are rarely found in cerebrospinal fluid; however, their presence is associated with meningitis. Chronic coccidioidal pulmonary cavities are often accompanied by IgG and IgM precipitating antibodies.


Serologic testing for coccidioidomycosis should be considered when patients exhibit symptoms of meningeal infection and have lived in or traveled to areas where Coccidioides immitis/posadasii is endemic. Any history of exposure to the organism or travel cannot be overemphasized when coccidioidomycosis serologic tests are being considered.


Complement Fixation:

IgG antibody is detected by complement fixation (CF) testing. Any CF titer in cerebrospinal fluid (CSF) should be considered significant. A positive complement fixation test in un-concentrated CSF is diagnostic of meningitis.



IgM and IgG precipitins are rarely found in CSF. However, when present, they are diagnostic of meningitis (100% specific). Since the immunodiffusion test is 100% specific, it is helpful in interpreting CF results.

Clinical Reference

1. Larone D, Mitchell T, Walsh T: Histoplasma, blastomyces, coccidioides, and other dimorphic fungi causing systemic mycoses. In: Murray PR, Baron EJ, Pfaller MA, et al, eds. Manual of Clinical Microbiology. 7th ed. ASM Press, 1999:1260-1261

2. Ramanan P, Wengenack NL, Theel ES: Laboratory diagnosis for fungal infections. A review of current and future diagnostic assays. Clin Chest Med. 2017 Sep;38(3):535-554. doi: 10.1016/j.ccm.2017.04.013

Report Available

3 to 6 days

Method Name

Complement Fixation (CF) / Immunodiffusion (ID)


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

Testing Algorithm

For more information see Meningitis/Encephalitis Panel Algorithm.

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