Characterizing ability of serum potassium (K) and the serum K reference interval to flag hypokalemia or hyperkalemia as observed in plasma: A simulation study

•Serum K, positively shifted from plasma K, contains a component due to clotting.•We simulated a serum distribution for K from an observed plasma K distribution.•Simulation tracked all changes in classification (hypokalemia, hyperkalemia)•Sensitivity in serum for either hypokalemia or hyperkalemia in plasma was <60%•Plasma should be the definitively preferred specimen type for assessment of K.