Serum or plasma mass concentration of des-arginine L-lysine vasopressin (ADH)

What Is Vasopressin (ADH) and Why Is It Measured?

Vasopressin, or antidiuretic hormone (ADH), is a hormone produced in the brain’s hypothalamus and released by the pituitary gland. It plays a key role in controlling how much water your kidneys reabsorb, which directly influences urine output. When ADH levels are too high or too low, it can lead to conditions like excessive thirst, dehydration, or fluid imbalances. This test specifically measures a modified form of vasopressin (des-arginine L-lysine vasopressin) to assess its concentration in your bloodstream.

When Might This Test Be Ordered?

Your healthcare provider may recommend this test if you have symptoms like extreme thirst, unusual urine volume, or signs of fluid imbalance. It could also be used to evaluate conditions such as diabetes insipidus (a hormone disorder affecting water balance), kidney function, or certain neurological disorders. Doctors may also order it to monitor treatment responses in patients with known hormone-related conditions.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then sent to a lab for analysis using a specialized technique to measure the precise amount of the modified vasopressin hormone. The lab will separate serum or plasma from your blood and apply advanced methods to quantify the hormone’s concentration accurately.

What Do the Results Mean?

Results are typically reported as a mass concentration (in units such as picograms per milliliter or nanograms per milliliter). Higher than expected levels may suggest conditions like syndrome of inappropriate antidiuretic hormone secretion (SIADH), while lower levels could indicate diabetes insipidus or other fluid imbalance disorders. Your doctor will interpret the results in the context of your symptoms and medical history.