Assessing the Performance of Handheld Glucose Testing for Critical Care

Abstract

Background: We assessed the performance of a point-of-care (POC) glucose meter system (GMS) with multitasking test strip by using the locally-smoothed (LS) median absolute difference (MAD) curve method in conjunction with a modified Bland-Altman difference plot and superimposed International Organization for Standardization (ISO) 15197 tolerance bands. We analyzed performance for tight glycemic control (TGC). Methods: A modified glucose oxidase enzyme with a multilayer-gold, multielectrode, four-well test strip (StatStrip™, NOVA Biomedical, Waltham, MA) was used. There was no test strip calibration code. Pragmatic comparison was done of GMS results versus paired plasma glucose measurements from chemistry analyzers in clinical laboratories. Venous samples (n = 1,703) were analyzed at 35 hospitals that used 20 types of chemistry analyzers. Erroneous results were identified using the Bland-Altman plot and ISO 15197 criteria. Discrepant values were analyzed for the TGC interval of 80–110 mg/dL. Results: The GMS met ISO 15197 guidelines; 98.6% (410 of 416) of observations were within tolerance for glucose y = 1.018x – 0.716 mg/dL, and r² = 0.995. Conclusions: LS MAD curves draw on human ability to discriminate performance visually. LS MAD curve and ISO 15197 performance were acceptable for TGC. POC and reference glucose calibration should be harmonized and standardized.