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Abstract

Introduction: Invasive Aspergillosis (IA) can cause significant morbidity and mortality in pediatric cancer patients. The Galactomannan enzyme immunoassay (GM-EIA) has shown promising results to diagnose IA in adult patients. But data on this assay in children are limited by small sample size and conflicting results. We evaluated GM-EIA at different cut off in pediatric cancer patients on chemotherapy with fever and neutropenia and not responding to broad spectrum antibiotics for four days. Aim: To Evaluate Galactomannan at different cut off values in 200 pediatric cancer patients. Materials and Methods: It is a hospital based cross sectional cohort study in pediatric cancer patients. Serum specimens were collected either once or twice weekly, during neutropenic periods. Operating characteristics were calculated using the GM-EIA index values (IV) of 0.5, 0.7. 1.0 & 1.5 in serum samples. Results: 232 serum samples from 200 febrile neutropenic patients were available for evaluation. Of these 232 samples 168 samples were single samples and 32 were consecutive samples (received twice in a week). GM assay was evaluated in both single and consecutive samples at different cut off IV. For single sample the best cut off IV was found to be 1.5 IV. Sensitivity, specificity, PPV, NPV, PLR and NLR at 1. 5 IV were: 78, 86, 79, 83, 4.83, and 0.20 respectively. For consecutive samples the best cut off IV was found to be 0.5 at which the sensitivity, specificity, PPV, NPV, PLR and NLR were: 84.2, 86.46, 83.73, 85.50,5.82 and 0.18 respectively. Conclusion:Role of single sample cannot be ruled out in establishing the diagnosis of IA in pediatric cancer patients especially in resource poor settings where frequent sampling is not possible. The best cut off IV of GM for diagnosis of IA in pediatric cancer patients in single serum sample is 1.5 and in consecutive sample is 0.5. MATERIALS AND METHODSThe study collection and stored at -20°C until analysis.2-3 ml of blood were collected in pediatric biphasic blood culture bottle prior to the administration of antimicrobials and were incubated aerobically at 37˚C and checked every day up to 7 days and then twice a week for up to 4 weeks, unless evidence of microbial growth was observed, subculture was done on Sabouraud's dextrose agar (SDA) plates, and incubated at 37°C and 25°C. The blood cultures were considered as negative after four weeks of incubation.[10]. GM levels in serum was measured by using Platelia Aspergillus enzyme immunoassay test (Bio Rad, Platelia, Marnes, La Coquette, France) as per the manufacturer instructions. Results were recorded as indexes relative to the mean OD of the threshold controls. Samples that had GM IV of ≥ 0.5 were considered as positive. Second samples of the patients were considered as independent episode if it was received after 4 week apart from the previous one, with the patient becoming clinically well between this duration. All these samples were also evaluated at 0.7, 1.0 and 1.5 IV.Decision for the start of antifungal prophylaxis...