VASOPRESSIN LEVEL - This test measures the amount of ADH in the serum. It is used to detect disorders that may affect the level of ADH in the serum. Normal values are: 0 to 4.7 pg/ml. Elevated ADH levels can indicate a CNS infection, fluid imbalance, CNS tumor, SIADH, or acute porphyria. Low levels can indicate: diabetes insipidus or damage to the pituitary gland.