A long-term case study on marginal diabetes: demonstrating the need for effective calibration of home test devices

Abstract

Accurate tracking of the trend in time of marginal diabetes level is not simple, as the precision of non-professional home testers is typically ±10–12 mg/dL—45% of the marginal range. A reliable assessment of the current calibration of home testers is difficult because it depends on the quality of the off-shell calibration and then on its subsequent validity in time. The paper reports test results specifically following a case of initial deterioration of the pancreas functionality, with the patient subsequently having to follow a strict diet with also assumption of Glucophage. The study carried out on its evolution made it possible to propose, with examples, a valid test procedure for optimising the performance of home testing without strictly requiring professional expertise, supplementing scarce/insufficient manufacturer information. The effect of the medical treatment was taken under observation for a total of ≈2300 morning glucose home tests over 8 years using several home testers models. The aim of the paper is not about the validity of the test method, but about getting evidence of the basic importance of the calibration of the testing devices, of its validity and sufficient accuracy, to improve the odds of a correct medical diagnosis—and patient confidence.