Why Culture Still Matters in Candida Diagnostics: Essential Insights from Global Guidelines

Despite advances in biomarkers and molecular assays, the guideline underscores that culture remains the primary and most reliable method for detecting Candida spp. across both superficial and invasive infections. Culture also remains the only method that reliably yields an isolate for downstream testing, including species identification and antifungal susceptibility profiling.

Blood culture—optimally using two to three sets of bottles with adequate blood volume—continues to be the gold standard for diagnosing candidemia. Direct microscopy and fungal culture are equally important for tissue and fluid samples, enhancing diagnostic yield while providing the context needed to differentiate colonization from true infection. Chromogenic and selective culture media play a key role here, enabling rapid presumptive identification and the detection of mixed-species infections, which occur frequently in high-risk surgical and transplant patients.

While molecular diagnostics can offer speed, the article highlights significant limitations that prevent their use as frontline diagnostics for most patient groups. Current assays detect only a subset of Candida species, and in-house methods lack robust clinical validation. As a result, molecular detection is only moderately supported, mainly reserved for scenarios in which alternative methods (such as MALDI-TOF MS) are unavailable or where rapid identification of high-risk species may influence immediate infection control measures.

Thus, although molecular techniques and biomarkers can complement diagnostic workflows, they are not recommended to replace culture, which remains essential for detection and differentiation and susceptibility testing.

Accurate, species-level identification guides targeted therapy and supports infection surveillance. Chromogenic media are strongly recommended for detecting mixed infections and are moderately supported for presumptive species identification. Culture provides isolates that can be definitively identified by MALDI-TOF MS or sequencing—both strongly recommended by the guideline—and serves as the foundation for epidemiological monitoring, outbreak detection, and stewardship decision-making.

The guideline strongly recommends antifungal susceptibility testing (AFST) for all invasive infections and for mucocutaneous infections failing therapy. AFST relies on viable isolates obtained through culture, reaffirming culture’s central role in the full diagnostic workflow. EUCAST and CLSI methods remain the standards, with CDC-defined tentative breakpoints guiding interpretation specifically for Candida auris.

The guideline strongly recommends antifungal susceptibility testing (AFST) for all invasive infections and for mucocutaneous infections failing therapy. AFST relies on viable isolates obtained through culture, reaffirming culture’s central role in the full diagnostic workflow. EUCAST and CLSI methods remain the standards, with CDC-defined tentative breakpoints guiding interpretation specifically for Candida auris.

At Thermo Scientific, we are committed to supporting laboratories with high-quality diagnostic solutions. Our new chromogenic Thermo Scientific™ Brilliance™ Candida 2 Agar enables detection and differentiation of Candida species, including direct identification of Candida auris, strengthening culture-centered workflows. Thermo Scientific manual identification solutions can further support species identification. 

Our susceptibility testing solutions, Thermo Scientific Oxoid AST Discs for flexible disc diffusion testing and the popular Thermo Scientific Sensititre YeastONE* broth microdilution system for minimum inhibitory concentration (MIC) testing, further support the clinical decision making by helping guide patient therapy options. These solutions are designed to help laboratories implement the full, guideline-aligned diagnostic pathway for Candida infections.

Learn more about our Candida testing solutions and get in contact with us.

*Thermo Scientific Sensititre YeastONE solution is validated against the CLSI reference method and should be interpreted by utilizing CLSI breakpoints only. Sensititre YeastONE has not been validated with Candida auris isolates for In-Vitro-Diagnostics use.