Background: Because extreme venous potassium abnormality can be life threatening, rapid measurement of
potassium level is essential. Traditional biochemical analysis for venous potassium takes time and delays
management in seriously ill patients. Analysis form arterial blood gas (ABG) may be an alternative method
that is faster.

Objective: To determine agreement between potassium obtained from venous and arterial blood gas in
emergency patients, Siriraj Hospital.

Material and Method: Cross-sectional study performed in 53 patients who presented to the emergency department
of Siriraj Hospital. Potassium level measured from ABG was compared to venous route.

Results: The mean of venous, arterial potassium and difference between each pair were 3.95, 3.46, and 0.49
mmol/L respectively. The Intraclass Correlation Coefficient between each pair of two methods and 95% CI of
agreement were 0.904 and 0.839 to 0.943, p < 0.01.

Conclusion: The agreement between ABG and venous potassium measurement are confirmed. Clinicians can
use ABG’s potassium level as a guideline for treatment instead of using the conventional venous potassium
level.

Keywords: Arteries, Blood gas analysis, Potassium