Evaluate electrolytes, acid-base balance, water balance. Chloride generally increases and decreases with plasma or serum sodium.

Chloride is increased in dehydration, with ammonium chloride administration, with renal tubular acidosis (hyperchloremic metabolic acidosis) and with excessive infusion of normal saline. Differential diagnosis of acidemias and alkalemias. Chloride is higher in hyperparathyroidism than in some of the other causes of hypercalcemia, but a great deal of overlap exists.

Chloride is decreased with overhydration, congestive failure, syndrome of inappropriate secretion of ADH, vomiting, gastric suction, chronic respiratory acidosis, Addison disease, salt-losing nephritis, burns, metabolic alkalosis, and in some instances of diuretic therapy.

Like other electrolytes, chloride cannot be interpreted without clinical knowledge of the patient. A diagnostic approach to the evaluation of hyperchloremic metabolic acidosis includes use of the urinary anion gap in conjunction with measurement of plasma potassium and urinary pH.¹

1. Batlle DC, Hizon M, Cohen E, Gutterman C, Gupta R. The use of the urinary anion gap in the diagnosis of hyperchloremic metabolic acidosis. N Engl J Med. 1988 Mar 10; 318(10):594-599. PubMed 3344005