Accurate Blood Glucose Measurement Methods

Laboratory Methods

The American Diabetes Association recommends enzymatic methods using hexokinase or glucose oxidase as the most standardized and accurate techniques for glucose measurement 1, 2
Laboratory methods demonstrate minimal imprecision with a coefficient of variation (CV) ≤2.7% at clinically relevant glucose concentrations, according to the American Association for Clinical Chemistry 1
The College of American Pathologists suggests that these methods are used in virtually all clinical laboratories in the US and provide consistent results across different facilities 1

The International Organization for Standardization states that glucose meters should have >95% of readings within ±15 mg/dL for glucose <75 mg/dL and within 20% for higher values 4
The American Medical Association notes that operator-related errors are more significant than instrument-related errors with glucose meters 4
Many meters fail to meet the International Organization for Standardization standards in real-world clinical settings, particularly in critically ill patients, as reported by the Society of Critical Care Medicine 5, 6

The American Association for Clinical Chemistry recommends plasma over whole blood for diagnostic purposes 1, 2
The National Institute of Diabetes and Digestive and Kidney Diseases states that glucose concentrations in plasma are approximately 11% higher than in whole blood with normal hematocrit due to higher water content in plasma 1, 2
The Clinical and Laboratory Standards Institute notes that most modern glucose meters are calibrated to provide plasma-equivalent readings 4

The Society of Critical Care Medicine recommends arterial or venous whole blood sampling over capillary (fingerstick) testing for critically ill patients, especially for patients in shock, on vasopressors, or with peripheral edema 5
The American Thoracic Society states that plasma glucose values from arterial blood are approximately 0.2 mmol/L higher than peripheral venous blood 6
Several factors can affect glucose meter accuracy in ICU settings, including anemia, hypoxia, and certain medications, as reported by the Society of Critical Care Medicine 8, 5

The American Association for Clinical Chemistry notes that low hematocrit can falsely elevate glucose meter readings due to lower erythrocyte mass 4
The Clinical and Laboratory Standards Institute states that improper storage of test strips (exposure to humidity or excessive temperature) can falsely elevate results 4
The National Institute of Diabetes and Digestive and Kidney Diseases reports that certain drugs like ascorbic acid, acetaminophen, dopamine, and mannitol can interfere with some glucose meter readings 4

The American Diabetes Association suggests a CV ≤2.2% as a target for imprecision, with 0% bias for plasma glucose 1
The College of American Pathologists states that the goal for glucose analysis should be to minimize total analytical error and methods should be without measurable bias 1
The American Association for Clinical Chemistry notes that significant bias (up to 13%) has been observed in some laboratory methods, which could lead to misclassification of individuals near diagnostic thresholds 1