Clinical Performance of the STANDARD™ G6PD Test in India

Background and objectiveG6PD enzyme deficiency is a genetic condition that can lead to acute hemolysis. This study evaluates the clinical performance of the point-of-care STANDARD G6PD Test in Kolkata, India, an area of high incidence of urban vivax malaria. MethodsEvaluation of the STANDARD G6PD Test was performed against a reference G6PD assay using UV-spectrophotometry in a febrile population (N=951) recruited from outpatient clinics. Hemoglobin performance was compared to automated hematology analyzer measurements from venous blood. Genotyping was performed on a subset of samples including all deficients/intermediates to identify variants. ResultsG6PD deficiency was 2.8%. 20.4% of the study population and had either moderate or severe anemia at enrollment. The tests sensitivity and specificity were 100% (95% CI: 87.2%- 100%) and 97.8% (96.3%-98.8%), respectively, for G6PD deficient cases. Sensitivity and specificity for females with intermediate G6PD activity were 62.5 % (35.4%-84.8%) and 96.1% (93.3%-98.0%), respectively. Female intermediates with false normal G6PD results had reference G6PD activity greater than 45%. Among malaria-positive individuals (N=272), the test showed 100% sensitivity for both deficient and intermediate G6PD cases. Fifteen participants were identified as Orissa, 1 as Mahidol and 2 as Mediterranean variants. All severe anemia cases (n=24) were accurately categorized as such by STANDARD G6PD test. Interpretation and conclusionThe STANDARD G6PD Test tested at the fever clinic setting was reliable in diagnosing patients at greatest risk of drug induced hemolysis and supports safe treatment of P. vivax in this population.