What is the role of a vasopressin stimulation test in the diagnosis of hypopituitarism (panhypopituitarism)?

Updated: Jun 09, 2020
  • Author: Bernard Corenblum, MD, FRCPC; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Answer

At the time of stability of the urine osmolarity, a vasopressin stimulation test may assist in discriminating between central and nephrogenic diabetes insipidus. Administer either 5 units of aqueous vasopressin or 1-2 mcg of desmopressin (DDAVP) subcutaneously. After 1 hour, acquire an additional set of serum and urine specimens. An increase in urine osmolality and a decrease in serum osmolality support a central cause of diabetes insipidus and a lack of arginine vasopressin (AVP). If osmolalities remain unchanged, the patient has nephrogenic diabetes insipidus (resistance to AVP).

This test is with some limitations in interpretation, so added serum measurements of AVP or copeptin (the C terminus of the vasopressin precursor) may improve test interpretation.


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