26342 Histoplasma Antibody, Serum (SHSTO)

​​​Fungal serology, Histo, Histoplasma capsulatum, Histoplasma Complement Fixation, Histoplasmosis, Immunodiffusion Serology for Fungi

​Aiding in the diagnosis of active histoplasmosis using serum specimens

Gross Hemolysis

Gross Lipemia

Recent histoplasmosis skin tests must be avoided because the test causes a misleading rise in complement fixation titer, as well as an M precipitin band, in approximately 17% of patients having previous exposure to Histoplasma capsulatum.

Cross-reacting antibodies sometimes present interpretive problems in patients having blastomycosis or coccidioidomycosis.

​Histoplasma capsulatum is a soil saprophyte that grows well in soil enriched with bird droppings. The usual disease is self-limited, affects the lungs, and is asymptomatic. Chronic cavitary pulmonary disease, disseminated disease, and meningitis may occur and can be fatal, especially in young children and in immunosuppressed patients.

​Complement fixation (CF) titers of 1:32 or higher indicate active disease. A rising CF titer is associated with progressive infection.

Positive immunodiffusion test results supplement findings of the CF test. The simultaneous appearance of both H and M precipitin bands indicates active histoplasmosis. The M precipitin band alone indicates early or chronic disease or a recent histoplasmosis skin test.

Patients infected with Histoplasma capsulatum demonstrate a serum antibody with a rising titer within 6 weeks of infection. A rising titer is associated with progressive infection. Specific antibody persists for a few weeks to a year, regardless of clinical improvement.