Water deprivation test

What is a water deprivation test?

A water deprivation test lets us see how concentrated your urine becomes when you do not drink anything. This test lets us see if you have diabetes insipidus. The test may take all day and some children need to stay overnight. It depends on how quickly your urine concentrates.

What is diabetes insipidus?

Diabetes insipidus is where the pituitary gland (a tiny part of your brain) does not release a hormone called antidiuretic hormone (ADH) or when your kidneys do not respond to it to control urine production properly.

How does the test work?

You will be admitted to the ward either the night before or on the day of the test. We will weigh you when you come in and a few times throughout the test.

The nurses will measure how much fluid you drink and how much you urinate during the test.

We will take some blood samples before, during and after your test.

The easiest way to do this is with a cannula in the vein in the back of your hand or arm. We will give you a local anaesthetic cream or cold spray to help with any pain or discomfort.

Each blood sample and urine sample is taken to a laboratory for tests.

Once the cannula is in, you can play with toys, read books and watch TV.

During you test your parent or carer and nurses will keep an eye on you to make sure you are okay.

What about drinking before the test?

You cannot drink anything before the test. Please check your appointment letter for the exact details

What about side effects?

There is a very small risk that you could become very dehydrated but we will keep a close eye on you to make sure you are okay. The nurses will stop the test if they are worried.

You will probably feel tired and not enjoy the test but it is important to keep going with the test to get the results. We know it is a hard but you are not allowed to drink anything at all. If you do, we will have to stop the test and try again another day.

Medications

Prescribed medications should be taken as normal prior to admission unless otherwise advised. Please bring with you all medications that your child is taking.

What happens after my test?

You will not be discharged until you have recovered from the test.

It is best if you can arrange your own transport home in a car rather than public transport as you can be very tired after the test.

You should be able to return to your normal activities the following day.

Specific care instructions will be given prior to discharge by the nurse performing the test.

When will I get my results?

The results of the test will take about a month to be analysed. Your consultant may write to you with the results or discuss them at your next appointment.