Diagnosis is usually based on the family history, physical exam, and imaging tests. Ultrasound and CT scans are commonly used imaging tests to show the kidney abnormalities.
In difficult cases without the usual findings, a kidney biopsy may be needed to make the diagnosis. This is a procedure that involves inserting a special needle through the skin and into the kidney. The needle is used to remove a tiny piece of the kidney, which can be sent to the lab for evaluation and testing.