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|82550:COCCIDIOIDAL SEROLOGY, IDENTIFICATION BY CF|
|Alias Names:||VALLEY FEVER, COCCI ABS ID/CF|
|Methodology:||Complement Fixation (CF); Immunodiffusion (ID)|
|Released:||7-10 days after setup at PeaceHealth Laboratories’ reference lab.|
|Specimen Collection Details|
|Collection:||One 7.5 mL serum separator tube (SST) or cerebrospinal fluid (CSF). Also acceptable: CSF Supernate.|
|Handling:||Allow to clot, centrifuge and separate serum from cells and pour into a plastic vial and refrigerate. If CSF, please include source of CSF (e.g., lumbar, cisternal or ventricular).|
|Standard Volume:||3 mL serum or CSF.|
|Minimum Volume:||2 mL serum or CSF.|
Immunodiffusion (ID) – presence or not of precipitin (IgM) or CF (IgG) antibody. The IgM is important in the diagnosis of acute primary coccidioidomycosis, and is detectable in most patients in 1 to 2 weeks after onset of symptoms, may persist several months, occasionally longer in association with a pulmonary cavity or disseminated disease. Presence of IgM in the CSF is associated with coccidioidal meningitis.
The CF (IgG) can be associated with a recent infection but can be detected in the serum months or years after the initial infection. Once positive, the qualitative immunodiffusion test may not need to be repeated.
|Complement fixation (CF) – reactivity given as 4+, 3+, 2+, 1+ or no (“0“) fixation of complement at serial dilutions of specimen. 4+ is significant CF (or 3+ provided immunodiffusion is also positive). 2+ and 1+ are not significant. A rising titer is unfavorable – titer greater than 1:16 in the serum is often associated with metapulmonary dissemination, but a lower titer can be associated with limited dissemination e.g., single osseous, cutaneous or meningeal involvement. CF by the CSF is usually indicative of coccidioidal meningitis but the IgG can be detected in the CSF in the absence of meningitis. Approximately 5% of patients with coccidioidal meningitis may initially have CSF negative by CF.|