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 ₂ ) of the applied blood sample. Because assessing the potential influence of pO ₂ when measuring capillary blood samples is not straight-forward, we performed a proof of concept study.
Method: Influence of pO ₂ 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 ₂ -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 ₂ 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 ₂ influence.
Results: The relative bias between the lowest and highest pO ₂ values differed by 14.3% for BGMS A, indicating a pO ₂ influence that might be clinically relevant, and by 9.7% for BGMS B, indicating that pO ₂ 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 ₂ in capillary blood samples on GOx-based BGMS could be detected. Further larger-scale studies are needed to verify this influence.