Influence of partial pressure of oxygen in blood samples on measurement performance in glucose-oxidase-based systems for self-monitoring of blood glucose

Abstract

Background: Partial pressure of oxygen (pO2) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO2 values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not.

Methods: Aliquots of 20 venous samples were adjusted to the following pO2 values: <45, ~70, and ≥150 mmHg. For each system, five consecutive measurements on each sample aliquot were performed using the same test strip lot. Relative differences between the mean BG results at pO2 ~70 mmHg, which is considered to be similar to pO2 in capillary blood samples, and the mean BG result at pO2 <45 and ≥150 mmHg were calculated.

Results: For all tested GOx systems, mean relative differences in the BG measurement results were between 6.1% and 22.6% at pO2 <45 mmHg and between -7.9% and -14.9% at pO2 ≥150 mmHg. For both pO2 levels, relative differences of all tested GOx systems were significant (p < .0001). The GDH system showed mean relative differences of -1.0% and -0.4% at pO2 values <45 and ≥150 mmHg, respectively, which were not significant.

Conclusions: These data suggest that capillary blood pO2 variations lead to clinically relevant BG measurement deviations in GOx systems, even in GOx systems that are not labeled as being oxygen sensitive.

© 2013 Diabetes Technology Society.

Figures

Figure 1.

Normalized relative differences at pO2 values <45 and ≥150 mmHg are displayed for the respective BG concentration (20 samples each, 5 measurements per sample). Normalized relative differences at pO2 value ~70 mmHg were set to zero (see Data Analysis).

Figure 2.

Normalized relative differences of BG measurements are plotted for pO2 values <45 and ≥150 mmHg, respectively (20 samples each, 5 measurements per sample). Normalized relative difference at pO2 value ~70 mmHg were set to zero (see Data Analysis). For systems 1 and 2, sensitivity to increased blood pO2 was labeled in the package inserts. For systems 3, 4, and 5, potential influences of pO2 on measurement results were not indicated in their user manual/package inserts.