Accuracy Evaluation of Four Blood Glucose Monitoring Systems in Unaltered Blood Samples in the Low Glycemic Range and Blood Samples in the Concentration Range Defined by ISO 15197

Introduction: Systems for self-monitoring of blood glucose (SMBG) are expected to be accurate enough to provide reliable measurement results. Especially in the low glycemic range, adequate therapeutic decisions based on reliable results can alleviate complications associated with hypoglycemia.

Materials and methods: The accuracy of four SMBG systems (system 1 was the ACCU-CHEK(®) Aviva [Roche Diagnostics GmbH, Mannheim, Germany], system 2 was the Contour(®) XT [Bayer Consumer Care AG, Basel, Switzerland], system 3 was the GlucoCheck XL [aktivmed GmbH, Augsberg, Germany], and system 4 was the GlucoMen(®) LX PLUS [A. Menarini Diagnostics S.r.l., Florence, Italy]) with three test-strip lots each was evaluated by calculating mean absolute relative differences (MARDs). Two datasets were evaluated: (1) 100 samples with blood glucose concentrations <70 mg/dL and (2) 100 samples distributed following International Organization for Standardization (ISO) standard 15197. Each sample was measured twice with each test-strip lot of each SMBG system. Comparison measurement results were obtained with a glucose oxidase method and a hexokinase method, both traceable according to ISO 17511. Analysis of variance of the MARD between the SMBG system and the comparison method was performed.

Results: MARD values ranged from 4.4% to 13.4% (<70 mg/dL) and 4.8% to 8.9% (ISO 15197-distributed) and differed significantly, with systems 1 and 2 showing lower MARDs than systems 3 and 4. MARD values deviated by up to 2.5% (corresponding to a relative deviation of approximately 40%) between the two comparison methods.

Conclusions: The investigated SMBG systems showed a significant variation of accuracy (measured by MARD), especially with higher MARD values in the low glycemic range. The selected comparison method had an impact on the MARD and therefore on the apparent accuracy of the SMBG systems. Sufficient measurement accuracy in the low glycemic range is required to enable users to react adequately to hypoglycemia.