<prompt> Which of the following statements about Diabetes Insipidus is true -Urine osmolality should be 300 mosmLPlasma osmolality should be 280 mmolLWater deprivation test is requiredPlasma osmolality should be 300 mosmL prior to H2O Deprivation test  <response>: In diabetes insipidus, urine is not maximally concentrated osmolality below 600 mOsmkg in the presence of increased plasma osmolality greater than 300 mOsmkg. The diagnosis can be confirmed or refuted by random simultaeous samples of blood and urine, but more often a dynamic test like water deprivation test is required. Reference : page 794 Davidsons Principles and practice of Medicine 22nd edition 