What laboratory findings would you expect in a patient with diabetes insipidus?

In a patient with diabetes insipidus, you would expect to see hypernatremia and increased serum osmolality. This condition occurs when there is a deficiency of antidiuretic hormone (ADH), which leads to the kidneys' inability to concentrate urine properly. As a result, the patient excretes large volumes of dilute urine, causing an increase in serum sodium levels due to the loss of free water.

The increased serum osmolality reflects the higher concentration of solutes in the blood, primarily sodium, due to insufficient water reabsorption. Additionally, the urine osmolality is decreased, as the kidneys are unable to reabsorb water effectively and thus produce a high volume of dilute urine. Consequently, the laboratory findings characteristic of diabetes insipidus include hypernatremia, increased serum osmolality, and decreased urine osmolality, leading to the selection of this answer as the most appropriate representation of the condition's physiological changes.