Self‑monitoring of Blood Glucose can be Misleading without Periodic Re‑calibration of Glucose Meters: A Pilot Study

Abstract

Introduction/Background: Diabetes mellitus is highly prevalent in both developed and developing countries today affecting about 429
million adults globally and is expected to rise by 147% to 629 million in 2045. Effective management of diabetes mellitus requires the
periodic measurement of fasting plasma glucose. Self‑monitoring blood glucose has been used to achieve this for over three decades
now. This study, therefore, assesses the performance of three blood glucose meters used by patients with diabetes in our environment.

Materials and Methods: This study adopted a comparative analytical prospective design that involved three of the frequently used glucose meters in our environment namely RUBY®, ONCALL®, and FINETEST®. Glucose calibrators of increasing concentrations from 40 mg/dL to 200 mg/dL were prepared from a freshly constituted 1800 mg/dl stock solution of glucose. Sera obtained from five patients were assayed along with control sera using a routine laboratory method (glucose oxidase [GOX]) for standardization and the three glucose meters simultaneously and the results were compared for statistical differences on Microsoft Excel using means and standard deviation. P ≤ 0.05 was set as a level of significance.

Results: The mean glucose values of calibrators (120 ± 63.3) were statistically significantly different from the mean glucose values of the RUBY (139.6 ± 80.9), (P = 0.0118) and the ONCALL (188.8 ± 82.1), (P ≤ 0.0001) glucose meters, respectively. The percentage increase in blood glucose estimation by the RUBY and ONCALL devices was 115.8% and 157.3% respectively. The FINETEST glucose meter overestimated glucose by 232.0% higher than the laboratory GOX method even though there was no statistical significance (P = 0.062) between the two means. The percentage imprecision for the different glucose meters was: RUBY 9.5%, FINETEST 14.8%, and ONCALL 18.2%.

Conclusion: Quality control should be used routinely in the use of point of care testing glucose measurements and devices should be
sent to the central laboratory periodically for recalibration to avoid mismanagement of diabetic patients on hypoglycaemic drugs.

Keywords: Diabetes mellitus, point of care testing, self‑monitoring of blood glucose