PURPOSE: Antigen detection strategies are often incorporated into the diagnostic approach to fungal diseases in immunocompromised hosts. Antigen testing in serum and urine is well established and testing diverse biological fluids such as cerebrospinal fluid and bronchoalveolar lavage (BAL) is useful in select patients. Antigen detection in BAL fluid has shown increased sensitivity and specificity for aspergillosis and histoplasmosis over serum testing alone1. Recently, antigen testing for coccidioidomycosis has been available but not extensively studied2.
METHODS: Coccidioidomycosis antigen testing was performed on 16 routinely discarded BAL samples obtained for clinical and research purposes. The BAL procedure was not standardized and the clinically important area was sampled as dictated by the clinical procedure. Coccidioidomycosis antigen testing was performed using the MiraVista(r) assay with and without an ethylenediaminetetraacetic acid (EDTA) step.
RESULTS: In a random sample of 16 BALs, in which pulmonary coccidioidomycosis was suspected in 2 patients, BAL was negative for antigen detection in all 16 samples. One sample converted to positive after treatment with an EDTA step. Two out of five subjects had positive serologic testing and were suspected to have past or resolving Coccidioides infection. No BAL samples grew Coccidioides.
CONCLUSION: In a highly endemic area of coccidioidomycosis, BAL antigen testing does not appear to capture low level background exposure to Coccidioides.
CLINICAL IMPLICATIONS: BAL antigen detection is likely to be most useful as an adjunct in the diagnosis of patients with acute, active pulmonary coccidioidomycosis infection where antigen burden would be high. References: 1.Hage CA, Wheat J, Knox KS et al. Diagnosis of histoplasmosis by antigen detection in BAL fluid. Chest 2010;137(3):623-628 2.Durkin M, Estok L. et al. Detection of Coccidioides antigenemia following dissociation of immune complexes. Clin Vaccine Immunol. 2009 Oct;16(10):1453-6.
DISCLOSURE: Oluwole Onadeko, No Financial Disclosure Information; No Product/Research Disclosure Information