Difficulties of the Water Deprivation Test (2)	

The water deprivation test is difficult to perform correctly, unpleasant for the patient (who may drink surreptitiously during the test), and relies heavily on the patient's ability to empty the bladder completely. For these reasons, it is far from ideal. Furthermore, the stimulus to vasopressin secretion is a combination of hypertonicity and hypovolaemia, especially towards the end of the period of dehydration.