How Are Kidney Stones Diagnosed?
Sometimes "silent" stones—those that do not cause symptoms—are found on X-rays taken during a general health exam. These stones would likely pass unnoticed. More often, kidney stones are found on an X-ray or ultrasound taken on someone who complains of blood in the urine or sudden pain. These diagnostic images give the doctor valuable information about the stone's size and location. Blood tests and urine tests help detect any abnormal substance that might promote stone formation.
The doctor may decide to scan the urinary system using a special X-ray test called an IVP (intravenous pyelogram). Together, the results from these tests help determine the proper treatment.
Fortunately, most stones can be treated without surgery. Most kidney stones can pass through the urinary system with plenty of water (2 to 3 quarts a day) to help move the stone along. In most cases, a person can stay home during this process, taking pain medicine as needed. The doctor usually asks the patient to save the passed stone(s) for testing. Stones can be extracted through surgery or dissolved with ultrasound waves.
People who have had more than one kidney stone are likely to form another. Therefore, prevention is very important. To prevent stones from forming, their cause must be determined. The urologist will order laboratory tests, including urine tests and blood tests . He or she will also ask about the patient's medical history, occupation and dietary habits. If a stone has been removed, or if the patient has passed a stone and saved it, the lab can analyze the stone to determine its composition.
A patient may be asked to collect his or her urine for 24 hours after a stone has passed or been removed. The sample is used to measure urine volume and levels of acidity, calcium, sodium, uric acid, oxalate, citrate, and creatinine (a byproduct of protein metabolism). The doctor will use this information to determine the cause of the stone. A second 24-hour urine collection may be needed to determine if the prescribed treatment is working.
