Evaluation of Potential Interference Caused by Endogenous Substances, Drugs, and Variations of Blood Sample...

Point-of-care (POC) strip-based blood glucose monitoring systems (BGMSs) used by health care professionals must be more robust than those used for patient self-testing, due to a higher likelihood of BG interferents present in the blood of hospitalized patients. The Cobas® Pulse system (Roche Diagnostics GmbH, Mannheim, Germany) is a novel strip-based POC BGMS designed for multiple patient use in professional health care environments. We report a series of experiments evaluating the effects of several potential interferents, and of extreme conditions, on the BGMS's performance.

Blood samples were spiked with glucose and various potential interferents or tested at extreme environmental conditions. Studies were performed using three lots of Cobas glucose test strips (Roche Diagnostics GmbH, Mannheim, Germany). Interference results over all test strip lots are expressed as the absolute or relative mean bias between test and control.

Compared with control, the mean absolute or relative bias did not exceed ±10 mg/dL or ±10% for any endogenous substance or drug tested, any combination of hematocrit level or glucose concentration over the ranges tested, or any test at altitudes up to 4300 m above sea level, with any of the three test strip lots. Varying oxygen concentrations (partial pressure) in a blood sample did not affect glucose measurements. All interference results were within the specified accuracy limits. Contamination of blood samples with skin disinfectants, extreme levels of ascorbic acid, or hematocrit levels outside the claimed range did not cause wrong test results.

POC BGMS performance was not altered by interfering substances after a rigorous evaluation under a wide range of conditions.