Aktualisierte Anforderungen an die Messqualität und Qualitätssicherung (QS) von Point-of-Care-Testing(POCT)-Blutglukose-Messsystemen mit Unit-use-Reagenzien, die für die Erstdiagnostik eines manifesten Diabetes in der Schwangerschaft oder eines Gestationsdiabetes mellitus (GDM) gemäß der GDM-Leitlinie der Deutschen Diabetes Gesellschaft (DDG) geeignet sind

Are all glucose solutions used for oGTT equal?

AIMS

Oral glucose tolerance tests (oGTT) are widely used for the diagnosis of diabetes. It is well known that the reproducibility of oGTT is poor and that a number of factors have an impact on the outcome of this diagnostic test. It appears as if one aspect, the oral glucose solution (OGS) used has not achieved much attention. Very little is published about this, despite the fact that apparently most often not a pure and freshly prepared glucose solution is used but a ready-to-use solution prepared by a (pharmaceutical) company.

METHODS

A literature search was performed to find respective publications.

RESULTS

It appears as if no or only a small number of not adequately designed clinical-experimental studies have been performed comparing different OGS head-to-head.

CONCLUSIONS

The composition of such OGS, including the excipients added to improve taste and smell, can have an impact on blood glucose increase after drinking the given OGS. Such factors can also have an impact on endogenous insulin secretion. If significant differences in the blood glucose excursions exist depending on which OGS is used, this calls for the use of a standardized OGS in oGTT to have a comparable outcome everywhere.

[Analytical Quality of Glucose Measurements in Germany]

The measurement quality of systems used for determination of glucose concentrations has to be sufficiently high to obtain measurement results that are reliable in a clinical context regarding the intended use (e. g., diabetes diagnosis and monitoring). The "Richtlinie der Bundesärztekammer zur Qualitätssicherung laboratoriumsmedizinischer Untersuchungen" (guideline of the German Medical Association on quality assurance in medical laboratory examinations) includes specifications on the internal and external quality assurance that are legally binding for glucose measurements in healthcare. In the opinion of the authors, however, there is room for improvement, and examples are provided. Systems for self-monitoring of blood glucose by patients do not fall under any legally binding requirements for quality assurance. With systems for continuous glucose monitoring, there are currently no technological means to regularly check measurement quality. Additionally, repeated manufacturer-independent evaluations, which could lead to improved measurement quality, are not available.

Measurement accuracy of two professional-use systems for point-of-care testing of blood glucose

Background The professional-use systems HemoCue® Glucose 201+ (HC201+) and HemoCue® Glucose 201 RT (HC201RT) are widely used for point-of-care testing (POCT) of blood glucose (BG). HC201RT utilizes unit-use microcuvettes which can be stored at room temperature, whereas HC201+ microcuvettes have to be stored at <8 °C. In this study, system accuracy of HC201+ and HC201RT was evaluated using capillary and venous blood samples. Methods For each system, two reagent system lots were evaluated within a period of 2 years based on testing procedures of ISO 15197:2013, a standard applicable for self-monitoring of blood glucose (SMBG) systems. For each reagent system lot, the investigation was performed by using 100 capillary and 95 to 99 venous blood samples. Comparison measurements were performed with a hexokinase laboratory method. Accuracy criteria of ISO 15197:2013 and POCT12-A3 were applied. In addition, bias was analyzed according to Bland and Altman, and error grid analysis was performed. Results When measuring capillary samples, both systems fulfilled accuracy requirements of ISO 15197:2013 and POCT12-A3 with the investigated reagent system lots. When measuring venous samples, only HC201+ fulfilled these requirements. Bias between HC201+ and reference measurements was more consistent over venous and capillary samples and microcuvette lots than for HC201RT. Error grid analysis showed that clinical actions might have been different depending on which system was used. Conclusions In this study, HC201+ showed a high level of accuracy irrespective of the sample type (capillary or venous). In contrast, HC201RT measurement results were markedly affected by the type of sample.