Clinical significance of low-positive histoplasma urine antigen results.

Histoplasma urine antigen (UAg) detection is an important biomarker for histoplasmosis. The clinical significance of low-positive (<0.6 ng/ml) UAg results was evaluated in 25 patients without evidence of prior Histoplasma infection. UAg results from 12/25 (48%) patients were considered falsely positive, suggesting that low-positive UAg values should be interpreted cautiously.