Diagnosis of histoplasmosis based upon detection of antigen

A negative result does not preclude a diagnosis of histoplasmosis. This assay has been documented to cross-react with Blastomyces dermatitidis, Coccidioides immitis, Paracoccidioides brasiliensis and Penicillium marneffei. Positive tests should be confirmed in areas or patient groups where these organisms are endemic or a risk. The following substances may interfere with the assay results: foods that produce color in urine, vaginal cream, caffeine, ascorbic acid, itraconazole, amphotericin B, acetaminophen and acetylsalicylic acid.

Screw cap plastic container (sterile)

Collect specimen aseptically

Transfer a 10 mL urine aliquot to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as urine

Transfer vial/tube with cap - 12mL (LabCorp)

Refrigerated (preferred) - 14 days

Frozen - 14 days

Ambient - NO

• Specimen not refrigerated or frozen
• Insufficient specimen volume
• Inappropriate specimen source
• Urine submitted with preservative such as boric acid

Enzyme immunoassay (EIA)

<0.2 ng/mL

Antigen detection may be useful in acute disease, especially in individuals also infected with HIV, who frequently have the disseminated form of histoplasmosis without detectable antibodies to the fungus. In chronic disease, antigen may not be detected due to the low fungal burden. The highest sensitivity for rapidly and accurately diagnosing histoplasmosis in patients with acute pulmonary or disseminated infection can be obtained by testing both urine and serum.