With its high sensitivity and specificity, an enzyme-linked immunosorbent assay (ELISA) test of the urine can detect Histoplasma antigen in up to 90% of patients with disseminated histoplasmosis.1 The organism can be cultured in sputum specimens in about 20% to 60% of cases, but the cultures can take between 3 and 6 weeks to become positive if Histoplasma is present. Occasionally, blood cultures also will be positive in patients with disseminated histoplasmosis, especially if the lysis centrifugation technique is used. A peripheral smear would not aid in the diagnosis of histoplasmosis. Although abnormalities would be seen on computed tomography of the chest, a microbiologic diagnosis would still be needed.
- Urine test.
1. Mandell GL, Bennett JE, Dolin R. Principles and practice of infectious diseases. 6th ed. Philadelphia: Churchill Livingstone; 2005.
Click here to return to the questions
Seminars in Medical Practice
Hospital Physician Board Review Manuals
Copyright © 2009, Turner White Communications
Updated 1/04/08 kkj