Diagnosing Kidney Stones

Kidney stones are common: Nearly one in 10 Americans is diagnosed with one at some point. Without treatment and preventive efforts, half of all people who have been treated for one or more kidney stones develop another within five to 10 years.

At NYU Langone, our doctors treat people who have many types of kidney stones, including calcium oxalate, calcium phosphate, struvite, uric acid, and cystine.

Most kidney stones can be passed through the urinary tract, occasionally unnoticed. Larger stones, however, can cause irritation, obstruction, and pain. Some of the most common symptoms of kidney stones include pain in the side or groin, nausea, vomiting, fever, and blood in the urine.

Diagnostic Tests for Kidney Stones

Your doctor conducts an initial physical exam and may order several tests, including blood and urine tests and imaging exams, to determine whether you have kidney stones and to diagnose the particular type and location. If you have passed a stone or had one surgically treated, your doctor may analyze the stone to determine its type and suggest additional testing to find out if you have more.

All of these tests may be scheduled on the same day as your doctor’s visit. Our radiologists and urologists can also review the results of scans you’ve had done at other medical facilities.

Blood Tests

During your initial exam, your doctor may collect a small amount of blood in order to assess your kidney function, look for signs of infection, and test for factors that can contribute to the formation of kidney stones, such as high calcium levels, parathyroid hormone, and uric acid.

Urine Tests

Your doctor may analyze a sample of your urine in order to check for crystals, which can lead to the formation of kidney stones, and order a urine culture to determine if you have a urinary tract infection. He or she may also ask you to collect urine at home for 24 hours or more, using containers that are supplied by the doctor’s office. This gives your doctors additional information about the presence of metabolic factors that can influence the formation of kidney stones in the urinary tract.

Ultrasound

Your doctor may recommend an ultrasound scan to evaluate your kidneys, bladder, and ureters, which are the tubes that carry urine from the kidneys to the bladder. This helps your doctor to check for stones that haven’t passed, to monitor the growth of a stone, and to screen for recurrence. In this test, a handheld device called a transducer is placed on the abdomen and used to produce sound waves that create images of the pelvic organs.

Kidney-Ureter-Bladder X-ray

A kidney-ureter-bladder, or KUB, X-ray of the abdomen and pelvis can help doctors to determine whether a kidney stone has grown, passed, or returned.

CT Scan

Your doctor may use a CT scan to look for stones in the kidneys, ureters, and bladder to determine their size and exact location, and to evaluate the anatomy of your urinary tract. At NYU Langone, doctors regularly use low-dose CT scans, which provide images of the abdomen and pelvis while minimizing your radiation exposure. Another kind of CT scan, called dual-energy CT, can help to determine the kidney stone type.

MRI Scans

MRI scans, in which magnetic waves are used to create computerized two- or three-dimensional images, are not typically used to evaluate kidney stones. However, this procedure, which does not use radiation, can sometimes help to safely diagnose kidney stones in pregnant women. Our urologists have experience managing kidney stones during pregnancy, and work closely with NYU Langone obstetricians to do so.