What's the lab name of the test that would tell me if I had a problem with the ADH (vasopressin)? I'm getting tested for other things & want to make sure it's there

Several tests needed. You need several tests (blood and urine) to confirm that a patient has a problem with antidiuretic hormone, including urine osmolarity, serum osmolarity, urine sodium, serum sodium, urine specific gravity. A CT of the head may also be needed.