How is diabetes insipidus diagnosed?

Diabetes insipidus is diagnosed primarily through blood and urine tests that assess concentration levels. In this condition, the body is unable to concentrate urine due to a lack of adequate antidiuretic hormone (ADH) or due to a resistance to the hormone, leading to excessive urination and increased thirst.

To confirm the diagnosis, healthcare providers typically perform urine osmolality tests and serum osmolality tests. In individuals with diabetes insipidus, urine osmolality is low, indicating dilute urine, while serum osmolality may be elevated due to dehydration and increased thirst. These tests help differentiate diabetes insipidus from other conditions that cause similar symptoms, such as diabetes mellitus.

While other diagnostic methods may provide additional information about the patient’s overall health or explore other potential causes of polyuria, the use of blood and urine tests specifically evaluates the kidneys' ability to concentrate urine, which is central to diagnosing diabetes insipidus effectively.