How Doctors Diagnose Kidney Cancer

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Doctor and patient exam

For symptoms of kidney cancer—such as blood in your urine, pain in your side or back, or a mass or lump on your side or back—your doctor will ask you to undergo certain tests to understand why you are experiencing symptoms. Test results and other diagnostic strategies help your doctor rule out or confirm a cancer diagnosis. The more you know about the tests your doctor may order, the more prepared you’ll be when you make your appointment. 

Diagnosing Kidney Cancer

Many tests are available to help doctors make a kidney cancer diagnosis. Your doctor uses some of these tests to confirm earlier test results, to determine the extent or spread of cancer, and to evaluate whether a treatment is effective at fighting the cancer.

Physical exam

Your doctor will check your abdomen and back for lumps or other signs of a kidney or urinary tract problem. He or she might also order a urinalysis to test your urine for signs of disease. A special test called a urine cytology checks for cancer cells in your urine, which can indicate cancer in the renal pelvis, ureter, or bladder rather than in the kidneys.

Blood tests

Blood tests you will have include:

  • Complete blood count (CBC): A CBC checks for the total amounts of red and white blood cells and platelets in your blood. A CBC, as well as routine blood tests, can help the doctor understand your overall health. A CBC is also one of several tests to determine if you are healthy enough for surgery if necessary.

  • Blood chemistry tests: Different from routine blood tests and CBCs, a blood chemistry test shows the levels of specific chemicals in the blood, such as your liver enzymes and blood calcium levels. You may need additional blood tests depending on the test results.

Imaging tests

Imaging tests are an important part of diagnosing kidney cancer. Possible tests include:

  • CT (or CAT) scan: A CT (computed tomography) scan is an imaging test that creates a three-dimensional (3D) picture of the inside of your body. These pictures can show the size and shape of kidney tumors, as well as whether they have spread to nearby lymph nodes, organs or tissues. CT scans are used more often than other imaging tests to help doctors make a kidney cancer diagnosis.

  • MRI: An MRI (magnetic resonance imaging) scan also creates a detailed 3D picture of your body. Unlike CT, no ionizing radiation is used. Your doctor may order an MRI to see whether cancer has spread to the abdominal blood vessels, brain, or spinal cord.

  • Ultrasound: Ultrasound images can reveal a mass on the kidneys and whether it is solid or filled with fluid.

  • PET scan: A PET (positron emission tomography) scan is a very sensitive type of imaging test that shows if the cancer is growing or has spread to nearby lymph nodes or other sites in your body. A PET scan can detect cancer before it creates a visible mass by CT, MRI or ultrasound, so it is useful when your doctor starts to evaluate treatment success.

  • Angiography: Using a special contrast dye, this type of X-ray reveals your network of blood vessels, including those supplying your kidneys. It helps your doctor diagnose kidney cancer and helps a surgeon prepare a plan for kidney cancer surgery.

  • Chest X-ray: A chest X-ray shows if cancer has spread (metastasized) to the lungs. Metastasis to the lungs usually only happens in the later stages of kidney cancer. For this reason, doctors do not typically rely on a chest X-ray for an initial kidney cancer diagnosis.

  • Cystoscopy and nephron-ureteroscopy: If a CT scan or other imaging test reveals a mass in the bladder, your doctor might also order these two tests to determine whether you have renal pelvic cancer.


A biopsy is a small sample of tissue to check for cancer cells. It is rarely used to diagnose kidney cancer because imaging tests are usually sufficient to determine if you need surgery. If cancer is not clear from the imaging tests, a biopsy of the mass will absolutely confirm or rule out a kidney cancer diagnosis. A biopsy taken during surgery to remove kidney cancer is important for kidney cancer staging and prognosis.

Next Steps After Kidney Cancer Diagnosis

If your doctor confirms you have kidney cancer, the next step is to plan a treatment with the best chances of success. The stage of kidney cancer helps determine the most appropriate treatment. It also helps your doctor predict the outcome of cancer, or your prognosis. When determining a treatment plan, your doctor will take into account your age and general health, as well as whether the cancer has spread. Surgery is often the first line of defense. Other treatments can include targeted therapy, immunotherapy, radiation therapy, and radiosurgery. A combination of these might also be an option.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Feb 18
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