Reducing Potential Medical Errors in Point-of-Care Testing

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Abstract
The objective of this study was to determine if heparin or ethylenediaminetetraacetic acid (EDTA) affected whole-blood glucose measurements obtained with test strips and common handheld meter systems. Lithium heparin (15 USP units/mL), potassium (K2) EDTA (1.8 mg/dL), and no-additive aliquots of venous blood from fifty-five diabetic patients were tested using four handheld glucose meter systems: the SureStep Pro and the One Touch II (Lifescan, Milpitas, CA), the Precision PCx (Abbott Laboratories, MediSense Products, Bedford, MA), and the Accu-Chek Comfort Curve (Roche Diagnostics, Indianapolis, IN), and a the YSI 2700 reference analyzer (Yellow Springs Instruments, Yellow Springs, OH). Coefficients of variation for within-day and between-day precision ranged from 1.4% to 6.8% for the glucose meter systems. Heparin and EDTA produce system-specific effects. Anticoagulant versus no-additive test strip comparisons showed that the SureStep Pro, with heparin and EDTA, and the Precision PCx, with EDTA, produced statistically significant negative mean paired differences. Heparin minimized the frequency of errors in glucose meter results. Heparinized samples produced the lowest frequency of discrepant meter results outside clinical error tolerances (± 15 mg/dL, glucose ≤ 100 mg/dL; ± 15%, glucose > 100 mg/dL) when compared with YSI 2700 reference results for paired samples. Specimen restrictions arise from anticoagulant selection, hematocrit range, physiological factors, and processing time. To reduce the potential for medical errors, the relative effects of different specimen anticoagulants should be considered carefully when conducting comparison studies, planning clinical applications, and interpreting glucose results.