Water deprivation test

When is this performed?

• When diabetes insipidus is suspected

What does the test involve?

• In the first half of the test, there is complete avoidance of fluid intake whilst taking intermittent blood and urine samples and weight measurements. The second half of the test involves administration of a drug (Desmopressin) and free access to fluids with urine and blood sampling.

Are there any side-effects?

• This test may be associated with thirst. It is important that you follow instructions given to you and resist drinking in the first half. This will produce results that are easier for doctors to interpret.

How long does the test take and is admission to hospital required?
 

• The test takes about 10 hours and does not usually require admission
   

What should you tell your doctor? What medicines you take, particularly if you take Desmopressin or diuretics.