Evaluation of Biomarkers: Galactomannan and 1,3-Beta-D-Glucan Assay for the Diagnosis of Invasive Fungal Infections in Immunocompromised Patients from a Tertiary Care Centre

Abstract

Purpose: Due to limitations of traditional microbiological techniques, standardised fungal biomarker tests such as Galactomannan Index (GMI) and 1,3-beta-D-glucan (BDG) are being preferred for diagnosis of invasive fungal infections (IFIs). These tests have been extensively used in developed countries but seldom in developing countries. The present study was performed to evaluate these tests for the diagnosis of IFIs in immunocompromised patients at an Indian tertiary care centre. Materials and Methods: A retrospective hospital-based study was done in immunocompromised patients with clinical suspicion of IFI. The demographic, clinical, radiological and mycological details of the patients were recorded. The patients were categorised into proven, probable and no IFI (as per European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria). The sensitivity and specificity of BDG Fungitell and Platelia Aspergillus antigen assays was estimated. Results: A total of 70 consecutive patients were included, of which 41 had IFI (10 proven and 31 probable) while 29 had no IFI. A significant association was found between IFI and the presence of a central venous line (P = 0.035) and history of intake of T-cell immunosuppressants (P = 0.001). Median BDG values (pg/ml) in patients with proven IFI, probable IFI and no IFI were 300 (range: 70–500), 165 (range: 53–500) and 45 (range: 31–500), respectively. The receiver operating characteristic (ROC) curve analysis for BDG revealed an area under the curve of 0.995, sensitivity: 97.4% and specificity: 96.6% for IFI diagnosis. The ROC curve analysis of GMI revealed an AUC of 0.75 and 90% patients with invasive aspergillosis (IA) had positive GMI. Conclusion: BDG has good sensitivity and specificity for distinguishing IFI from no IFIs and GMI may be used for diagnosing IA.