Pourbiax Diagrams as an Aid to Understanding the Impact of Acid/Base Disturbance on Blood Glucose Point-of-Care Testing.

Objective: Assays based on redox reactions that involve proton transfer are vulnerable to artifactual findings in metabolic acidosis/alkalosis. We evaluated the impact of pH on the measurement of blood glucose by the glucose dehydrogenase/pyrroloquinoline quinone system used in point-of-care-testing.

Methods: We applied a series of thermodynamic equations to adjust the Gibbs energy for the pyrroloquinoline quinone couple.