title: 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.
authors.affiliation: Institut für Diabetes-Technologie Forschungs- und Entwicklungsgesellschaft mbH an der Universität Ulm, Helmholtzstrasse 20, 89081 Ulm, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Baumstark
authors.forename: Christina
authors.initials: C
authors.lastname: Schmid
authors.forename: Stefan
authors.initials: S
authors.lastname: Pleus
authors.forename: Cornelia
authors.initials: C
authors.lastname: Haug
authors.forename: Guido
authors.initials: G
authors.lastname: Freckmann
mesh_terms: D000328:Adult; D000368:Aged; D000531:Altitude; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation / Q000379:methods*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D005260:Female; D042843:Glucose 1-Dehydrogenase / Q000097:blood; D005949:Glucose Oxidase / Q000097:blood*; D006801:Humans; D008171:Lung Diseases / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010313:Partial Pressure; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D042843:Glucose 1-Dehydrogenase; D005949:Glucose Oxidase; D010100:Oxygen