Chloride ion (extracellular fluid concentration) (Cl⁻ (ECF concentration))

Chloride ion (Cl⁻) is the major extracellular fluid anion, making up about two-thirds of the ECF anion content, with a concentration commonly around 100–110 mM in plasma. The extracellular fluid chloride concentration is essential for maintaining electrical neutrality, osmolarity, and acid–base balance in the body. Chloride shifts between body compartments are closely regulated by the kidneys, chiefly through a network of tubular ion channels and transporters such as the sodium-chloride co-transporter (NCC) and sodium-potassium-chloride co-transporter (NKCC). Imbalance of extracellular chloride levels is clinically significant, manifesting in disorders such as hyperchloremia or hypochloremia, which are often reflective of underlying issues like dehydration, renal dysfunction, acid–base disturbances, or certain pulmonary disorders. Although extracellular chloride is not itself a therapeutic target, it is a critical parameter evaluated in disease diagnosis and management, especially in nephrology and critical care.

Other names

Chloride (Cl⁻)Extracellular chloridePlasma chlorideSerum chloride

Not directly targeted; drugs modulate chloride concentration by affecting renal reabsorption or excretion (e.g., inhibition of sodium-chloride co-transporter NCC, sodium-potassium-chloride co-transporter NKCC, or epithelial sodium channel ENaC)