Are Sodium and Potassium results on arterial blood gas analyzer equivalent to those on electrolyte analyzer?

The present study was conducted with the aim to compare the sodium (Na) and potassium (K) results on arterial blood gas (ABG) and electrolyte analyzers both of which use direct ion-selective electrode technology.

Materials and Methods:

This was a retrospective study in which data were collected for simultaneous ABG and serum electrolyte samples of a patient received in Biochemistry Laboratory from February to May 2015. The ABG samples received in heparinized syringes were processed on Radiometer ABL80 analyzer immediately. Electrolytes in serum sample were measured on ST�100 Sensa Core analyzer after centrifugation. Data were collected for 112 samples and analyzed with the help of Excel 2010 and Statistical software for Microsoft excel XLSTAT 2015 software.

Results:

The mean Na level in serum sample was 139.4 ± 8.2 mmol/L compared to 137.8 ± 10.5 mmol/L in ABG (P < 0.05). The mean difference between the results was 1.6 mmol/L. Mean K level in serum sample was 3.8 ± 0.9 mmol/L as compared to 3.7 ± 0.9 mmol/L in ABG sample (P < 0.05). The mean difference between the results was 0.14 mmol/L. Statistically, a significant difference was observed in the results of two instruments in low Na (Conclusions: The clinicians should be cautious in using the electrolyte results of electrolyte and ABG analyzer in inter exchangeable manner.
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