Serum potassium concentration

Serum potassium concentration measures the amount of free potassium ions in blood plasma. Potassium is predominantly an intracellular cation essential for maintaining resting membrane potential across cell membranes—critical for nerve impulse transmission and muscle contraction. The kidneys play the primary role in regulating total body and extracellular fluid levels through filtration, reabsorption, secretion mechanisms involving aldosterone-sensitive channels such as ENaC and ROMK. Insulin and beta adrenergic activity also influence internal distribution by promoting cellular uptake of K⁺ via Na/K ATPase activity. Abnormalities—either hypokalemia or hyperkalemia—are common clinical problems associated with significant morbidity due to their impact on excitable tissues like heart muscle; thus serum K⁺ is closely monitored during treatment with many cardiovascular or renal drugs.

Other names

Serum K⁺Blood potassium levelPlasma potassium concentration

Drugs alter serum potassium by: * Increasing renal excretion/reabsorption via effects on nephron transporters/channels or aldosterone signaling. * Shifting K⁺ between intracellular/extracellular compartments via Na⁺/K⁺ ATPase modulation or beta adrenergic stimulation/inhibition.