Serum vs plasma potassium – Cardiology MCQ – Answer
Comparing serum and plasma potassium values – Correct answer: 1. Serum values are higher by 0.1 to 0.4 mmol/l
Potassium is continuously released from cells during clotting. So serum values are higher than plasma values. So long waiting periods for analysis can cause spurious or pseudohyperkalemia. Same can occur if hemolysis occurs due to errors in collection.
João Pedro Ferreira, Javed Butler, Patrick Rossignol, Bertram Pitt, Stefan D Anker, Mikhail Kosiborod, Lars H Lund, George L Bakris, Matthew R Weir, Faiez Zannad. Abnormalities of Potassium in Heart Failure: JACC State-of-the-Art Review. J Am Coll Cardiol. 2020 Jun 9;75(22):2836-2850.