Electrolyte Monitoring in the ICU: Bridging the Gap Between Point-of-Care and Central Laboratory Discrepancies

Highlights

• Point-of-care direct potentiometry (DP) and central laboratory indirect potentiometry (IP) are not interchangeable for sodium (Na+) and potassium (K+) measurements in the ICU.
• Prospective data reveals a 95% limit of agreement for Na+ of 10.48 mmol/L, which exceeds clinically acceptable thresholds for acute management.
• Approximately 10% of electrolyte measurements result in discordant clinical classifications (e.g., normal vs. abnormal) when comparing the two methods.
• A significant knowledge gap exists among clinicians, with only 31.1% of surveyed physicians aware of the analytical biases inherent in indirect potentiometry.

Background