Value of the Cand-Tec Candida antigen assay in the diagnosis and therapy of systemic candidiasis in high-risk patients.

A total of 911 sera from 171 patients at risk for systemic candidiasis and 24 sera from 24 non-hospitalized control subjects were analyzed for the presence of candida antigen using a commercially available latex agglutination test (Cand-Tec). Thirty-seven (22%) patients had systemic candidiasis documented by positive blood cultures, deep biopsy culture and histopathology or autopsy. Six patients had transient candidemia, 20 patients had candiduria, 53 patients had mucous membrane colonization, 21 patients were not colonized but received empiric amphotericin B, and 34 patients were not colonized and not treated with amphotericin B. The intraobserver reproducibility was 90% for the exact titer and 100% for a deviation of one dilution. The sensitivity and specificity of the candida antigen test in detection of systemic candidiasis was 95% and 50% (greater than or equal to 1:2), 73% and 72% (greater than or equal to 1:4), and 46% and 80% (greater than or equal to 1:8) respectively. Despite the poor specificity, serial antigen determinations in patients with documented systemic candidiasis demonstrated both an early diagnostic and prognostic role for the candida antigen test. Seventy-one percent of patients whose antigen titer increased during the course of amphotericin B therapy of documented infection died versus only 13% of those whose titer decreased while on therapy (p = 0.01). The candida antigen test has a limited yet potentially useful role in the diagnosis and management of systemic candidiasis in high-risk patients.