Comparison of electrolyte test results on blood gas analyzer and automatic biochemistry analyzer

Electrolyte testing is often ordered clinically, especially important in patients treated in the intensive care unit (ICU). In addition to the requirement for the accuracy of results, the turnaround time testing also needs to be shortened to ensure care and treatment. Currently, laboratories can perform electrolyte tests on two systems, a blood gas analyzer and a routine biochemistry analyzer. This study aims to find the correlation between the results of electrolyte tests performed on blood gas analyzer and automatic biochemistry analyzer. The study was conducted on 910 patients who were assigned both arterial blood gas and electrolyte tests at the Laboratory Department - Hanoi Medical University Hospital. The results showed that a high correlation between electrolyte results performed on a blood gas machine and an automatic biochemistry analyzer (r: 0.751-0.874). The difference exceeded the allowable cut-off and depended on the concentration of these electrolytes in the blood. The mean differences of the concentrations of Na+, K+, and Cl- in the blood were 1.4254 [-4.233-7.084], -0.4874 [-1.337-0.363], and -0.8388 [-7.346-5.668], respectively. The difference in electrolyte results on the two systems is clinically significant, clinicians therefore should pay attention to the use of these test results.