Which electrolyte measurement is least affected by hemolysis?

Calcium is the electrolyte measurement that is least affected by hemolysis. When blood cells break down, certain electrolytes, most notably potassium, are released from the intracellular space into the serum, leading to elevated measurement levels. Conversely, calcium levels remain relatively stable despite hemolysis because the majority of calcium in the bloodstream exists in ionized form, largely unaffected by the release of intracellular contents.

In addition to calcium, magnesium levels also can be impacted by hemolysis, but to a lesser extent than potassium. Phosphate (Pi) levels can also rise due to hemolysis as phosphate is found in high concentrations within red blood cells. Thus, calcium's stability makes it the most reliable measurement in situations where hemolysis may occur, such as in patients with hemolytic anemia or when blood samples are mishandled prior to analysis.