Compatibility of Na and K values measured by biochemistry analyser and blood gas analyser in different clinical situations

Severe disturbances in sodium and potassium are frequently encountered in emergency departments and these are among the most important treatable medical emergencies. In this study we aimed to evaluate the correlation of serum sodium and potassium levels measured with blood gas analyser (BGA) and biochemistry laboratory autoanalyser (BLA) devices in the laboratory. We conducted a retrospective study between April 1st and 30th, in an emergency department of an university hospital. We screened patients whom had both venous blood gas analysis and serum electrolytes in biochemistry panel. Then we grouped electrolyte levels of patients as hyper-, hypo-, and eu- to compare these groups separately. Pearson correlation coefficients were calculated for determination linear relationships between the variables. Results: total of 156 patients (age> 18) screened whom had both venous blood gas analysis and serum electrolytes in biochemistry panel at the same emergency appointment. The mean level of sodium in serum samples was 138.7 mmol/l compared to 143.2 mmol/l in venous blood gas. Mean variation between two samples was -4.46 mmol/l (95% CI -5.25, -3.67), ranged from -19 mmol/l to 4 mmol/l. The mean level of potassium in serum samples was 4.34 mmol/l compared to 3.74 mmol/l in venous blood gas. Mean variation between two samples was 0.6 mmol/l (95% CI 0.50, 0.69) ranged from -0.50 mmol/l to 2.6 mmol/l. The correlation coefficient was found r=0.852 for Na, r=0.774 for K and p was <0.001 for both values. We found positive correlation in sodium and potassium levels in various strength in different clinical situations. As our opinion, blood gas analyses should help and guide physicians especially in emergent conditions.

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