Evaluation of the utility of serological tests in the diagnosis of candidemia

BACKGROUND: It has been observed that the incidence and prevalence of candida infections in critically ill non-immunocompromised patients has increased. This study aims to evaluate the utility of the use of serological tests (double immunodiffusion and Cand-Tec Test) for the determination of candidemia. METHODS: A retrospective evaluation is made of 214 patients admitted to the Intensive Care Unit (ICU) of the Agostino Gemelli University Polyclinic during a period of 42 months. The double immunodiffusion technique was utilized for the determination of Candida antibodies. The Cand-Tec latex agglutination test was performed to evaluate the presence of Candida antigen. Four hundred and fifty-five antigen and antibody tests were performed. RESULTS: Thirty-six patients (16.8%) developed an invasive candidiasis. The sensitivity and specificity of antibody detection tests was 29 and 67 respectively; the positive predictive value was 15 and the negative predictive value was 82. The sensitivity and specificity of the antigen detection test ranged between 82 and 3 and between 8 and 98 respectively according to different cut-off titre; the positive predictive value was low (13-17%) and the negative predictive value decreased from 70 to 29. CONCLUSIONS: The utility of the use of serological tests in the diagnosis of candidemia is extremely limited. The gold standard for the determination of Candida sepsis remains the demonstration of candida in blood or in tissues.