Quality Assessment of the Creatinine and Electrolytes Measurement in the Emergency Department

Background & Aims: The study aim was to validate the usability of a blood gas analyzer for the measurement of creatinine and electrolytes.Methods: A total of 190 patients were retrospectively investigated. Creatinine, sodium, potassium, and chloride concentrations in heparinized whole blood samples taken from an artery (103 patients) and vein (117 patients) measured with the blood gas analyzer and in serum measured in the laboratory were compared.Results: The bias and coefficient values for the measured concentrations between serum and heparinized whole blood taken from an artery were as follows: creatinine, －0.089 mg/dL, 0.966; sodium, 0.214 mEq/L, 0.906; potassium, 0.234 mEq/L, 0.860; chloride, －1.874 mEq/L, 0.924, respectively. The bias and coefficient values for the measured concentrations between serum and heparinized whole blood taken from a vein were as follows: creatinine: －0.12 mg/dL, 0.992; sodium: －0.829 mEq/L, 0.953; potassium: 0.132 mEq/L, 0.969; and chloride: －0.744 mEq/L, 0.951, respectively. Compared with the concentrations measured in the laboratory, the blood gas analyzer concentrations for creatinine and chloride were slightly higher, but that for potassium was slightly lower.Conclusion: Acceptable agreement was obtained between the blood gas analysis and the laboratory analysis of creatinine and electrolytes for use in time-critical clinical decision-making in the emergency department.