Antidiuretic Hormone (ADH) Test

Antidiuretic hormone (ADH) or vasopressin testing measures the level of this hormone in the plasma. It is secreted by the posterior pituitary gland and plays a key role in regulating the body's water and salt balance by influencing urine concentration. Measuring ADH levels helps diagnose disorders such as diabetes insipidus and syndrome of inappropriate ADH secretion (SIADH).