Background & Objective: Serum 1,3-β-D-glucan (BDG) is indicated as a tool for early diagnosis of invasive fungal Infections (IFIs). Although this assay has been evaluated well in adult patients, its role in diagnosis of IFI in paediatric cancer patients is said to be limited. One of the reasons for this could be the cut off value chosen for interpretation of the assay. Different studies have suggested different cut off values to diagnose IFI in adult patients by this assay. Most of the time only single serum samples are available from paediatric cancer patients, also serial testing is not possible due to high cost of the assay. This study was therefore planned with the objective to determine the assays best cut off value for the diagnosis of IFI by single serum samples in paediatric cancer patients. Methods: BDG was evaluated in paediatric cancer patients at risk of IFI, admitted at oncology unit of Department of Paediatrics, King George’s Medical University, Lucknow, Uttar Pradesh, India. Only single serum samples were analysed by Fungi tell assay. Results were analyzed for sensitivity, specificity, positive predictive value and negative predictive value at cut off values of 80, 100, 120, 140, 160, 180,200, 220, 240, 280and 320 pg/ml. Results & Interpretation: A total of 116 serum samples from116 patients (80 hematologic cancer and 36 solid tumour) were analyzed. As per receiver operating curve (ROC) analysis and You den index, 160 pg./ml was found to be the best cut off value by this assay to decide on IFI in single serum samples.
Conclusion: Serum BDG may be a useful test in paediatric cancer patient to diagnose IFI even when single serum samples are available, but the cut off value for interpretation must be kept higher. We suggest a cut off value of 160 pg/ml to diagnose IFI in paediatric cancer patients from single serum sample.