An evaluation of serodiagnostic tests in patients with candidemia: beta-glucan, mannan, candida antigen by Cand-Tec and D-arabinitol

Abstract

The serodiagnostic tests, beta-glucan, mannan, candida antigen by Cand-Tec, and D-arabinitol were evaluated in 10 patients with candidemia, 14 patients with suspected fungemia, and 10 healthy persons. By blood culture or lysis centrifugation, C. albicans was isolated from 5 patients, C. parapsilosis from 4, and C. tropicalis from 1 patient; no organisms were isolated from the 14 patients with suspected fungemia or the 10 healthy subjects. Beta-glucan was measured by the difference between two chromogenic limulus tests (Endotoxin test-D and Endospecy), which was more than 60 pg/ml in 7 of 9 (78%) candidemic patients and 1 of 12 (8%) patients with suspected fungemia. Mannan was positive in 6 of 10 (60%) candidemic patients and 1 of 13 (8%) patients with suspected fungemia. Both antigens were very sensitive and highly specific for candidemia. However, the Cand-Tec assay was less specific, because titers of more than 4 were observed in 5 of 14 (34%) patients with suspected fungemia. D-Arabinitol was the least sensitive, because a D-arabinitol/creatinine ratio greater than 2.0 mumol/mg was observed in only 2 of 7 (29%) candidemic patients. The titers of serodiagnostic tests decreased after successful treatment with an anti-fungal agent. Our results show that the combined use of the assays in necessary for accurate serological diagnosis of candidemia.