Oxygen Effects on Glucose Measurements with a Reference Analyzer and Three Handheld Meters

Oxygen may affect glucose meter and reference analyzer measurements. We evaluated the effects of changes in blood oxygen tension (Po₂) on Accu-Chek Comfort Curve (Roche Diagnostics, Indianapolis, IN),™ Precision G,™ (Abbott Laboratories, Bedford, MA) and One Touch II^® (Lifescan, Milpitas, CA) glucose meter measurements, and on Yellow Springs Instruments (YSI) (Yellow Springs, OH) reference analyzer measurements. Venous blood drawn from healthy volunteers was adjusted to three glucose levels of 80, 200, and 400 mg/dL, each tonometered with six different Po₂ levels(40, 80, 160, 240, 320, and 400 torr). To quantitate oxygen effects on reference analyzer measurements, glucose differences between test sample (Po changed) and control (Po 80 torr) were calculated (YSI_test-YSI_control). The threshold for determination of oxygen effects was ± 2 SD, where 2 SD was from YSI between-day precision evaluated with aqueous controls. To quantitate oxygen effects on glucose meter measurements, paired-differences between glucose meter and reference analyzer measurements were calculated (Meter-YSI). Error tolerances for determination of oxygen effects were (a) within ± 15 mg/dL of reference measurement at glucose levels ≤100 mg/dL, and (b) within ± 15% of reference measurement at glucose levels >100 mg/dL. All differences for the reference analyzer measurements were within ± 2 SD ranges. Increases in Po₂ lowered Precision G measurements. Differences exceeding the error tolerances ( ± 15 mg/dL or ± 15%) were mainly at Po₂ levels >100 torr. Glucose differences for the Accu-Chek Comfort Curve and One Touch II were within the error tolerances. Changes in Po₂ do not affect glucose measurements with the YSI reference analyzer, Accu-Chek Comfort Curve, and One Touch meter systems. High blood Po₂ levels (>100 torr) significantly decrease Precision G measurements. We recommend that health care professionals understand oxygen effects and use oxygen-insensitive meter systems for point-of-care glucose testing when patients are on oxygen ventilation or critically ill.