Which step is appropriate when sodium appears low with normal electrolytes?

Which step is appropriate when sodium appears low with normal electrolytes?

• A. Check for specimen glucose
• B. Rerun the electrolyte panel
• C. Measure potassium
• D. Check for hemolysis

Answer: (A)

A low sodium with normal other electrolytes often signals a dilutional effect from elevated glucose in the specimen. When glucose is high, water shifts from inside cells to the extracellular space, diluting sodium and making it appear low even though the actual sodium status isn’t truly reduced. Checking the specimen glucose helps determine if this hyponatremia is artifactual. If glucose is elevated, you’d correct the sodium value or repeat testing after glucose normalizes to reveal the true sodium level. The other steps—repeating the electrolyte panel, measuring potassium, or checking for hemolysis—don’t directly address this osmotic dilution mechanism, and thus are less informative in this scenario.

A low sodium with normal other electrolytes often signals a dilutional effect from elevated glucose in the specimen. When glucose is high, water shifts from inside cells to the extracellular space, diluting sodium and making it appear low even though the actual sodium status isn’t truly reduced. Checking the specimen glucose helps determine if this hyponatremia is artifactual. If glucose is elevated, you’d correct the sodium value or repeat testing after glucose normalizes to reveal the true sodium level. The other steps—repeating the electrolyte panel, measuring potassium, or checking for hemolysis—don’t directly address this osmotic dilution mechanism, and thus are less informative in this scenario.