Mannan antigenemia in the diagnosis of invasive Candida infections.

Because it is often difficult to diagnose invasive Candida infections, a sensitive hemagglutination inhibition assay to detect the surface antigen, mannan, was developed. Mannan antigenemia was detected early in the course of infection in 4 of 14 patients with systemic candidiasis and 2 of 5 patients with invasive gastrointestinal candidiasis. Mannan was not detected in 48 patients with noninvasive Candida or other systemic mycotic infections or in 99% of 234 patients in other control groups. Mannan antibodies were almost universally present in both candidiasis and control groups. In four patients with systemic candidiasis, an early period of mannan antigenemia was followed by a rapid rise in mannan antibody titer. These findings suggest that antemortem diagnosis would be improved in one-third of cases of invasive Candida infection detected by the hemagglutination inhibition assay. A positive test for serum mannan would be an early and specific signal of invasive disease.