Which lab tests are performed to confirm the diagnosis of diabetes insipidus (DI)?

Updated: Mar 18, 2020
  • Author: Romesh Khardori, MD, PhD, FACP; Chief Editor: George T Griffing, MD  more...
  • Print
Answer

In a patient whose clinical presentation suggests diabetes insipidus (DI), laboratory tests must be performed to confirm the diagnosis. A 24-hour urine collection for determination of urine volume is required. In addition, the clinician should measure the following:

  • Serum electrolytes and glucose

  • Urinary specific gravity

  • Simultaneous plasma and urinary osmolality

  • Plasma antidiuretic hormone (ADH) level

Perform testing with the patient maximally dehydrated as tolerated—that is, at a time when ADH release is the highest and his/her urine is the most concentrated. Water deprivation testing may be useful in situations in which the diagnosis is uncertain.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!