Proof of Concept Study to Assess the Influence of Oxygen Partial Pressure in Capillary Blood on SMBG Measurements.

Background: Measurement results provided by blood glucose monitoring systems (BGMS) can be affected by various influencing factors. For some BGMS using glucose oxidase (GOx)-based test strips, one of these factors is the oxygen partial pressure (pO) of the applied blood sample. Because assessing the potential influence of pO when measuring capillary blood samples is not straight-forward, we performed a proof of concept study.

Method: Influence of pO was investigated for two GOx-based BGMS (BGMS A and B). Measurement results of the GOx-based BGMS were compared with measurement results from a pO-independent BGMS (BGMS C). A total of 119 samples from 60 subjects were measured, twice with BGMS C, then 6 times each with BGMS A and BGMS B or vice versa, and again twice with BGMS C. Immediately afterward, pO was determined. Linear regression analysis based on relative differences between results from BGMS A or BGMS B and results from BGMS C was performed to estimate the degree of pO influence.

Results: The relative bias between the lowest and highest pO values differed by 14.3% for BGMS A, indicating a pO influence that might be clinically relevant, and by 9.7% for BGMS B, indicating that pO influence may be too small to be reliably detected because of the BGMS' imprecision.

Conclusions: This proof of concept study showed that with the procedures used, a potentially clinically relevant influence of pO in capillary blood samples on GOx-based BGMS could be detected. Further larger-scale studies are needed to verify this influence.