How do they discover kidney stones?

Imaging studies. All kidney stones are diagnosed by clinical history, urinalysis, and confirmed with some type of radiological study. The best test is a ct scan but it has the downside of a lot of radiation. Other tests that are useful inlcude a kub x-ray or kidney ultrasound.
CT Scan. Normally today, most stones are seen on a non-contrasted ct scan of the abdomen.