Diagnostic Biomarkers for Invasive Candidiasis: A Clinician-Oriented Review

A group of approximately 15 Candida species are frequently found to be responsible for human invasive candidiasis, an infection that appears in patients with prolonged hospitalization, particularly in Intensive Care Units, and in immunosuppressed individuals. Given the considerable burden if not rapidly treated, clinicians face diagnostic challenges in distinguishing infection. The objective of this narrative review is to summarize the clinically applicable biomarkers used for invasive candidiasis and to evaluate their performance and create a diagnostic algorithm for clinical practice.

This narrative review was conducted by searching PubMed and Scopus for studies published between 1990 and 2025, using keywords related to invasive candidiasis and non-culture diagnostic biomarkers. Clinical guidelines and consensus documents from major infectious diseases societies were additionally reviewed to supplement.

Blood cultures, which are considered the "gold standard" for diagnosis, face important fallouts caused by the limited sensitivity of 50%. Polymerase Chain Reaction assays can identify Candida species at an early stage when compared to blood cultures, demonstrating high specificity that ranges between 91% and 98, due to their high cost, and the limitations regarding only the identification of certain species, their widespread use remains limited. Non-culture serological tests such as mannan, anti-mannan and 1-3-β-D-glucan can detect fungal cell wall components or antibodies directed towards them. These tests have the advantage of being performed directly from blood samples. Reported sensitivity and specificity are 83% and 86% for mannan/anti-mannan, and 73% and 80% for 1-3-β-D-glucan, respectively. They are used for early detection of candidemia in high-risk patients, including immunocompromised individuals.

Our report suggests that the traditional "gold standard" for diagnosing invasive candidiasis can be improved by integrating and combining novel biomarkers in the diagnostic pathways, and, thus, potentially reducing the time spent for diagnosing and facilitating early treatment access.