Familial pseudohyperkalemia

Definition

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 in vitro 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.