Role of the Fungal Serological Marker Galactomannan Antigen in the Diagnosis of Invasive Fungal Infection: A Three-Year Retrospective Study.

Background and objectives Invasive fungal infections (IFIs) are the most prevalent potentially fatal opportunistic mycoses in immunocompromised individuals. Early detection is essential for treating these patients. Biomarkers, measured in blood or other clinical samples, are effective supplements to conventional pathologic and microbiologic diagnostic methods for IFIs. We conducted this study to determine the positivity of serum galactomannan (GM) in clinically diagnosed IFI. Also, we assessed the diagnostic power of GM for predicting invasive aspergillosis (IA), the most common cause of IFIs. Methodology This retrospective study analyzed clinically diagnosed patients with IFIs admitted to Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar, India, from January 2023 to December 2025. The study included the blood samples received for serum GM antigen testing during the study period. We evaluated the diagnostic performance of the GM antigen. We also plotted the receiver operating characteristic (ROC) curve and determined the area under the curve (AUC). Results We analyzed data from 172 clinically diagnosed patients with IFIs. Aspergillus flavus consistently showed the highest GM levels, followed closely by Aspergillus fumigatus and Aspergillus niger. The test demonstrated high sensitivity (82.4%) but low specificity (46.8%). The AUC was 0.69. Differences in age, gender distribution, and year-over-year prevalence were statistically significant (P < 0.001). Conclusions GM antigen detection is useful for identifying IA. It demonstrated improved sensitivity and specificity compared with conventional methods (potassium hydroxide (KOH) and culture). Future multicenter studies incorporating polymerase chain reaction (PCR) and β-D-glucan are warranted to validate these findings.