Biomarkers for Diagnosis of Candidal Infections

Abstract

Candidemia and invasive candidiasis are associated with significant mortality, in part because of inadequate diagnostic tests. The current gold standard is blood culture, which is negative in 50% of cases. As such, development of novel diagnostics is a top priority. In Europe, studies of combined mannan antigen and anti-mannan antibody detection assays have demonstrated sensitivity of 71–100% and specificity of 86–93%. In the United States, there is more experience with (1 → 3)-β-D-glucan detection as a broad-spectrum assay for fungal pathogens. Sensitivity and specificity for diagnosing invasive candidiasis have ranged widely in studies (47–95% and 76–100%, respectively). Nucleic acid detection assays such as polymerase chain reaction (PCR) are potentially powerful tools that are now approaching the clinic. Overall, optimized PCR assays have sensitivities and specificities for candidemia and proven or probable invasive candidiasis that exceed 90%. Studies to determine the precise clinical roles of non–culture-based diagnostics are in progress.