There are three other conditions that need to be considered when diagnosing cranial diabetes insipidus:
A water deprivation test is used in the diagnosis of cranial diabetes insipidus. The test usually starts at about 08.00 in the morning. The patient is then dehydrated for the next 8 hours with only dry food and limited water being allowed. The plasma/urine osmolality, body weight and urine volumes are then measured hourly. After 8 hours 2µg injection of desmopressin (synthetic vasopressin analogue) is given and the recordings continued.
The results of the test are interpreted as follows: