Thirty drugs used primarily in critical care and hospital settings were tested in vitro to observe interference on glucose measurements with 6 hand-held glucose meters and a portable glucose analyzer. Paired differences of glucose measurements between drug-spiked samples and unspiked control samples were calculated to determine bias. A criterion of +/- 6 mg/dL was used as the cutoff for interference. Ascorbic acid interfered with the measurements on all glucose devices evaluated. Acetaminophen, dopamine, and mannitol interfered with glucose measurements on some devices. Dose-response relationships help assessment of drug interference in clinical use. High dosages of these drugs may be given to critically ill patients or self-administered by patients without medical supervision. Package inserts for the glucose devices may not provide adequate warning information. Hence, we recommend that clinicians choose glucose devices carefully and interpret results cautiously when glucose measurements are performed during or after drug interventions.

Different oxygen tensions do not significantly affect glucose measured with the GD-based amperometric test strips, and have minimal effect on GO-based photometric test strips. Increases in oxygen tension lowered glucose measured with GO-based amperometric test strips. We recommend that the effects of different oxygen tensions in blood samples on glucose measurements be minimized by using oxygen-independent test strips for point-of-care glucose testing in critically ill and other patients with high or unpredictable blood Po2 levels.