Glucose measurements are among the most important analysis in clinical chemistry. Glucose concentrations can be determined with automated analyzers in medical laboratories or with point-of-care glucometers which are widely known from self-testing. This work evaluates glucose measurements of over 130,000 samples to assess analytical performance of different devices and their medical impact.
The diagnosis and treatment of diabetes mellitus relies heavily on measurements of blood glucose concentrations. With a worldwide prevalence of diabetes mellitus close to 7%, glucose measurements are among the most frequently performed analyses in medical laboratories.
Like other analytes, glucose can be measured with automated analyzers in medical laboratories. Additionally, portable glucometers which are widely known from self-testing are employed in professional settings as well. These point-of-care tests measure glucose immediately and close to the patient from capillary blood.
Regardless of the test type, participation in External Quality Assessments (EQA) are crucial to ensure continuous high quality in medical laboratories worldwide. In EQAs, samples with a known quantity of the analyte are send to participating laboratories. These laboratories analyze the sample and return their results. The EQA organizations evaluate the results to inform laboratories of their measurement performance.
In a research article published in Clinical Chemistry and Laboratory Medicine, researchers analyzed glucose testing data from the two German EQA organizations “Reference Institute for Bioanalytics” and “INSTAND – Gesellschaft zur Förderung der Qualitätssicherung in medizinischen Laboratorien” from the years 2012 to 2016.
The device employed had the highest influence on the probability to reach a “good” performance in all EQAs. Participation in an EQA for automated analyzers improved performance in EQAs for portable glucometers. The reciprocal effect was less pronounced. New participants performed worse than experienced participants, especially in EQAs for automated analyzers. Imprecision was generally smaller for automated analyzers, but some glucometers reached a comparable performance.
Large measurement differences of the same sample occurred only because different test strip lots for glucometers were used in over 10% of analyzed cases. Clinical risks of errors was greatest in the low range of measurement 60–115 mg/dL (3.3–6.4 mmol/L) for most devices. All results have to be interpreted with caution as stabilized samples in EQAs might behave differently compared to patient samples.
The evaluation of EQA data serves can serve as foundation for learning and improvement in the laboratory healthcare system.
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Andreas Bietenbeck, Wolf J. Geilenkeuser, Frank Klawonn, Michael Spannagl, Matthias Nauck, Astrid Petersmann, Markus A. Thaler, Christof Winter, Peter B. Luppa: External quality assessment schemes for glucose measurements in Germany: factors for successful participation, analytical performance and medical impact. 01.05.2018