Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

CIMRP
88804
rarely found in CSF. However, when present, they are diagnostic of meningitis (100% specific). Since
the ID test is 100% specific, it is helpful in interpreting CF results. Early primary antibody (IgM) found
in coccidioidomycosis can be detected by the IgM-specific ID test. IgM precipitins may be detectable
within 1 to 4 weeks after the onset of symptoms. The presence of IgG antibody parallels the CF
antibody and indicates an active or a recent asymptomatic infection with Coccidioides immitis. Both
IgG and IgM antibodies are rarely detected 6 months after infection. However, in some patients having
disseminated infection, both IgG and IgM antibodies may be present for several years. IgM and IgG
precipitins are not prognostic. An equivocal result (a band of nonidentity) cannot be interpreted as
significant for a specific diagnosis. However, this may be an indication that a patient should be followed
serologically. The sensitivity of serologic testing (CF and ID combined) for coccidioidomycosis is
>90% for primary symptomatic cases.
Reference Values:
COMPLEMENT FIXATION
Negative
If positive, results are titered.
IMMUNODIFFUSION
Negative
Results are reported as positive, negative, or equivocal.
Clinical References: Larone D, Mitchell T, Walsh T: Histoplasma, blastomyces, coccidioides, and
other dimorphic fungi causing systemic mycoses. In Manual of Clinical Microbiology. 7th edition. Edited
by PR Murray, EJ Baron, MA Pfaller, et al: Washington, DC, ASM Press, 1999, pp 1260-1261
Coccidioides immitis/posadasii, Molecular Detection, PCR
Clinical Information: Coccidioidomycosis is caused by the dimorphic fungi, Coccidioides immitis
and Coccidioides posadasii. These organisms are endemic to the southwestern regions of the United
States, northern Mexico, and areas of Central and South America. The illness commonly manifests as a
self-limited upper respiratory tract infection, but can also result in disseminated disease that may be
refractory to treatment.(1) Clinical onset generally occurs 10 to 16 days following inhalation of
coccidioidal spores (arthroconidia).(2) Disease progression may be rapid in previously healthy or
immunosuppressed individuals. At present, the gold standard for the diagnosis of coccidioidomycosis is
culture of the organism from clinical specimens. Culture is highly sensitive and, with the implementation
of DNA probe assays for confirmatory testing of culture isolates, yields excellent specificity.(3) However,
growth in culture may take up to several weeks. This often delays the diagnosis and treatment of infected
individuals. In addition, the propagation of Coccidioides species in the clinical laboratory is a significant
safety hazard to laboratory personnel, serving as an important cause of laboratory-acquired infections if
the organism is not quickly identified and handled appropriately (ie, in a Biosafety Level 3 facility).
Serological tests including immunodiffusion and complement fixation are widely used for the detection of
antibody against Coccidioides. Serology for Coccidioides can be limited by delays in antibody
development or nonspecificity due to cross-reactions with other fungi. In addition, immunodiffusion and
complement fixation tests are highly labor intensive and are generally limited to reference laboratories.
Molecular methods can identify Coccidioides species directly from clinical specimens, avoiding the need
for culture and allowing for a more rapid and safer diagnosis.
Useful For: Rapid detection of Coccidioides An aid in diagnosing coccidioidomycosis
Interpretation: A positive result indicates presence of Coccidioides DNA. A negative result indicates
absence of detectable Coccidioides DNA.
Reference Values:
Not applicable
Clinical References: 1. Chiller TM, Galgiani JN, Stevens DA: Coccidioidomycosis. Infect Dis Clin
North Am 2003;17:41-57 2. Feldman BS, Snyder LS: Primary pulmonary coccidioidomycosis. Semin
Respir Infect 2001;16:231-237 3. Padhye AA, Smith G, Standard, et al: Comparative evaluation of
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