Evaluation of a Candida antigen detection test (Cand-Tec) in the diagnosis of deep candidiasis in neutropenic patients.

The diagnostic efficiency of a serum Candida antigen detection test Cand-Tec test) was prospectively investigated in 104 leukemic patients treated by intensive chemotherapy or allogeneic bone marrow transplantation. Candida antigen titers were determined on admission and then weekly as long as patients remained neutropenic. Nine patients had a proven disseminated yeast infection (diagnosed only at autopsy in five cases). The highest Candida antigen titers were 1:2 in two patients and 1:4 or more in seven patients (sensitivity: 76% for this last titer). This highest titer was observed 12 days before to 3 days after the diagnosis. Seven out of the 97 patients without proven deep candidiasis had a maximum titer of 1:4 (specificity: 93%). The positive predictive value was 50% for a titer of 1:4 and 24% for a titer of 1:2, whereas the negative predictive value was 100% for a titer of 1:4 and 97% for a titer of 1:2. Patients with elevated titers were mostly treated by chemotherapy, were older and had a worse prognosis than those with negative titers, although the duration of neutropenia was similar. It is concluded that Candida antigen detection is a reliable method of diagnosis of deep candidiasis in neutropenic patients. The clinical interest in this test, with special regard to empiric antifungal therapy, is discussed.