Discrepancy in Chloride Measurement with Decreasing Bicarbonate Concentrations.

Abstract

Accurate chloride measurement is important in critically ill patients. Chloride concentration measured simultaneously between the central laboratory (indirect ion-selective electrode) and blood gas analysis (direct ion-selective electrode) were compared. We report a discrepancy with chloride measurement between the central laboratory and blood gas analysis at low bicarbonate levels. Caution should be applied while interpreting the chloride concentration when indirect ion-selective electrode methodology is used, especially in the setting of low serum bicarbonate levels.