How Kidney Stones Are Found

Kidney stones can become stuck in any part of the urinary system. To begin to locate a stone, doctors may perform an x-ray or ultrasound study. This gives a good idea of the stone’s size and where it is located. Many patients also receive an intravenous pyelogram (IVP). For an IVP, a special dye is injected into the patient’s vein. The dye eventually collects in the urinary system. There, it produces a white contrast when an x-ray is taken. The dye allows the doctor to precisely locate the stone and to determine the condition of the kidneys, ureters, and bladder.
It is very important that the stone, if passed, be saved, so that it can be sent to a laboratory for evaluation. Long-term treatment and prevention plans depend on the type of stone. Between 70% and 80% of stones pass on their own in the urine, usually within 48 hours of the start of the symptoms. To catch a stone, patients are asked to urinate into a strainer, a cup with mesh in the bottom. All pieces of stone, no matter how small, should be collected and given to the doctor. If one stone is analyzed, more may not be needed, since most people develop just one type of stone.