Diabetes Insipidus
Diagnosis

To diagnose diabetes insipidus, your doctor will ask you questions about your health and that of other family members, particularly if your doctor suspects you have the inherited form of the disease. Tests that may be administered include:

• Urinalysis This test examines the contents of your urine. If the water content is high and the salt and waste concentration low, it could be due to diabetes insipidus.
• Fluid or Water Deprivation Test This is a test to measure changes in your body weight, urine output and urine contents. Prior to this test, your doctor will measure your weight and collect a urine sample for analysis. Your doctor will ask you to stop drinking fluids for several hours. During this period, urine samples will be collected. Your doctor also may measure the blood levels of antidiuretic hormone (ADH) or vasopressin. For children and pregnant women, it's important that no more than 5 percent of body weight is lost during the test.
• Magnetic Resonance Imaging (MRI) An MRI scan of the head may be performed to look for abnormalities in or near the pituitary gland. This scan uses powerful magnets and radio waves to create detailed images of the brain.