<prompt> Normal plasma osmolality is285-300 milliosmokg310-340 milliosmokg200-240 milliosmokg160-180 milliosmokg  <response>: The normal value of plasma osmolality is 285-300 mosmkg.Osmolality is measured with an osmometer based on the depression of the freezing point of the sample.Patients with deficiency of ADH Central diabetes insipidus or a decreased response to ADH Nephrogenic diabetes insipidus will excrete urine with osmolality less than 300 mosmolskg.Ref: D M Vasudevan 7th edition Page no: 373 