Benchmarking Point-of-Care Glucometers: A Comparative Study Using the Hexokinase Test and International Organization for Standardization (ISO) Standards

Introduction The International Diabetes Federation states that India accounts for one in seven of all adults with diabetes. Adherence to self-monitoring of blood glucose is essential for effective management of diabetes. Despite the wide variety of glucometers and their clinical applicability, there is a lot of ambiguity regarding their accuracy. Therefore, this study aimed to evaluate if three point-of-care glucometers using three different methods for the estimation of blood glucose fulfil the minimum accuracy needed by ISO15197:2013 when compared with the gold standard hexokinase test. Methods A cross-sectional study was conducted at two primary health care centers in Ernakulam district, which included 73 participants with diabetes and 73 without diabetes. We evaluated three different enzymes in the test glucometers: glucose dehydrogenase with pyrroloquinoline quinone (GDH-PQQ), glucose dehydrogenase with flavin adenine dinucleotide (GDH-FAD), and glucose oxidase (GOD). The glucometer readings were compared with the gold standard hexokinase test and ISO15197:2013 standards. To compare the accuracy of each glucometer with the reference method, the Bland-Altman plot was used and to evaluate the clinical significance of the differences between the glucometer and reference value the Clarke error grid analysis was performed. Results When compared with the gold standard hexokinase result, only 78.08% (GOD), 92.4% (GDH-PQQ), and 95.8 (GDH-FAD) of results were within the limits stipulated by ISO15197:2013. All three glucometers showed blood glucose results within zones A and B of the consensus error grid, implying that it is clinically acceptable, and the Bland-Altman plot showed that the GDH-FAD method had the narrowest range between the upper and lower limit of agreement and a minimum bias of -0.89. Conclusion Only one test glucometer with the GDH-FAD method met the ISO15197:2013 criteria. Glucometers must meet the accuracy standards for the safety of the patients.