Familial pseudohyperkalemia

Familial pseudohyperkalemia (FP) is an inherited, mild, non-hemolytic subtype of hereditary stomatocytosis that is associated with a temperature-dependent anomaly in red cell membrane permeability to potassium that leads to high <i>in vitro</i> potassium levels in samples stored below 37°C. FP is not associated with additional hematological abnormalities, although affected individuals may show some mild abnormalities like macrocytosis.