Glucose Meters: A Review of Technical Challenges to Obtaining Accurate Results

Abstract

Glucose meters are universally utilized in the management of hypoglycemic and hyperglycemic disorders in a variety of healthcare settings. Establishing the accuracy of glucose meters, however, is challenging. Glucose meters can only analyze whole blood, and glucose is unstable in whole blood. Technical accuracy is defined as the closeness of agreement between a test result and the true value of that analyte. Truth for glucose is analysis by isotope dilution mass spectrometry, and frozen serum standards analyzed by this method are available from the National Institute of Standards and Technology. Truth for whole blood has not been established, and cells must be separated from the whole blood matrix before analysis by a method like isotope dilution mass spectrometry. Serum cannot be analyzed by glucose meters, and isotope dilution mass spectrometry is not commonly available in most hospitals and diabetes clinics to evaluate glucose meter accuracy. Consensus standards recommend comparing whole blood analysis on a glucose meter against plasma/serum centrifuged from a capillary specimen and analyzed by a clinical laboratory comparative method. Yet capillary samples may not provide sufficient volume to test by both methods, and venous samples may be used as an alternative when differences between venous and capillary blood are considered. There are thus multiple complexities involved in defining technical accuracy and no clear consensus among standards agencies and professional societies on accuracy criteria. Clinicians, however, are more concerned with clinical agreement of the glucose meter with a serum/plasma laboratory result. Acceptance criteria for clinical agreement vary across the range of glucose concentrations and depend on how the result will be used in screening or management of the patient. A variety of factors can affect glucose meter results, including operator technique, environmental exposure, and patient factors, such as medication, oxygen therapy, anemia, hypotension, and other disease states. This article reviews the challenges involved in obtaining accurate glucose meter results.

Consensus Report: The Current Role of Self-Monitoring of Blood Glucose in Non-Insulin-Treated Type 2 Diabetes

“…77,78 Seven factors account for inaccuracy in BG monitoring related to (1) patient performance, (2) strips, (3) physical environment, (4) physiology, (5) medications, (6) inherent system limitations, and (7) data processing. [78][79][80][81] Preanalytical errors are more of a concern for laboratory testing of analytes than for self-monitoring, because most preanalytical errors are due to procurement, handling, and storage of samples in preparation for subsequent testing. For SMBG, most preanalytical errors are related to patient performance in obtaining a blood specimen or storing strips.…”

Performance of a Blood Glucose Monitoring System in a Point-of-Care Setting

“…1,2 Handheld BGMS are easy to operate, and they deliver results quickly. This is of particular relevance in a hospital setting, where medically urgent cases may require fast and efficient treatment.…”

Assessing the Analytical Performance of Systems for Self-Monitoring of Blood Glucose: Concepts of Performance Evaluation and Definition of Metrological Key Terms

“…As ID-GC/MS is a very complex and time-consuming method that can only be handled by a few laboratories worldwide, manufacturers usually choose methods 19 that are easier to handle to calibrate their BG systems. These socalled "manufacturer's standing measurement procedures" should, however, preferably be calibrated by ID-GC/MS to guarantee an unbroken traceability chain.…”