Time course of blood gas analysis and application to inter-instrument difference verification using patient blood sample as a control

Abstract

  In recent years, testing equipment located inwards has been managed in a central laboratory, and the same is true for blood gas analyzers. We investigated the time course of blood gas analysis（BGA） using actual samples and attempted to apply it to the inter-instrument difference test of blood gas analyzers. Patients admitted to our hospital between October 2021 and March 2022 with BGA samples taken were analyzed after data collection. 5 mL of blood was collected into a blood collection tube containing heparin sodium, and continuous BGA testing was performed approximately every 2.5 minutes. The reference range for quality control was calculated from （the average） ±2×（standard deviation） of the amount of change obtained in 10 consecutive measurements. While pH and pO₂ increased over time, pCO₂, HCO₃^－, Ca²⁺, and glucose decreased. On the other hand, no obvious changes were observed in Na⁺, K⁺, Cl^－, and Lactate. In continuous BGA using 2 devices, the HCO₃^－ of all 3 patients and the pCO₂ of 2 out of 3 patients decreased beyond the reference range, suggesting differences between the devices, where improvement was observed after the maintenance of the electrode. From the above, the time course of BGA was clarified. Furthermore, it was considered that the present results could be applied to the inter-instrument difference test of blood gas analyzers using actual samples.