Tests for Kidney Cancer

Kidney cancer might be found because of signs or symptoms a person is having, or it might be found because of lab tests or imaging tests a person is getting for another reason. If cancer is suspected, tests will be needed to confirm the diagnosis.

Medical history and physical exam

If you have any signs or symptoms that suggest you might have kidney cancer, your doctor will want to take a complete medical history to check for risk factors and to learn more about your symptoms.

A physical exam can provide information about signs of kidney cancer and other health problems. For example, the doctor may be able to feel an abnormal mass (lump) when he or she examines your abdomen (belly).

If symptoms or the results of the physical exam suggest you might have kidney cancer, more tests will probably be done. These might include lab tests and imaging tests.

Blood tests

Lab tests cannot show for sure if a person has kidney cancer, but they can sometimes give the first hint that there may be a kidney problem. If cancer has already been diagnosed, they are also done to get a sense of a person’s overall health and to help tell if the cancer might have spread to other areas. They also can help show if a person is healthy enough to have an operation.

Urinalysis (urine testing): This test may be done if your doctor suspects a kidney problem.

Microscopic and chemical tests are done on a urine sample to look for small amounts of blood and other substances not seen with the naked eye. About half of all patients with renal cell cancer will have blood in their urine. If the patient has transitional cell carcinoma (in the renal pelvis, the ureter, or the bladder), sometimes a special exam of the urine sample (called urine cytology) in the lab will show actual cancer cells in the urine.

Complete blood count (CBC): This is a test that measures the amounts of different cells in the blood. This test result is often abnormal in people with renal cell cancer. Anemia (having too few red blood cells) is very common. Less often, a person may have too many red blood cells (called polycythemia) because the kidney cancer cells make a hormone (erythropoietin) that causes the bone marrow to make more red blood cells. Blood counts are also important to make sure a person is healthy enough for surgery.

Blood chemistry tests: These tests are usually done in people who might have kidney cancer, because the cancer can affect the levels of certain chemicals in the blood. For example, high levels of liver enzymes are sometimes found. High blood calcium levels may indicate that cancer has spread to the bones, and may therefore prompt a doctor to order a bone scan. Blood chemistry tests also look at kidney function, which is especially important if certain imaging tests or if surgery is planned.

Imaging tests to look for kidney cancer

Imaging tests use x-rays, magnetic fields, sound waves, or radioactive substances to create pictures of the inside of your body. Imaging tests can be done for a number of reasons, such as:

  • To look at suspicious areas that might be cancer
  • To learn how far cancer has spread
  • To help determine if treatment is working

Unlike most other cancers, doctors can often diagnose kidney cancer with fair certainty based on imaging tests without doing a biopsy (removing a sample of the tumor to be looked at under a microscope). In some patients, however, a biopsy may be needed.

Computed tomography (CT) scan

The CT scan uses x-rays to produce detailed cross-sectional images of your body. It is one of the most useful tests for finding and looking at a tumor in your kidney. It can provide precise information about the size, shape, and location of a tumor. It is also useful in checking to see if a cancer has spread to nearby lymph nodes or to organs and tissues outside the kidney. If a kidney biopsy is needed, this test can also be used to guide a biopsy needle into the mass (lump) to obtain a sample.

When a CT is done to look at the kidneys, an IV (intravenous) contrast dye is often needed to make certain areas stand out better on the scan. This CT contrast can damage the kidneys. This happens more often in patients whose kidneys are not working well in the first place. Because of this, your kidney function will be checked with a blood test before you get IV contrast.

Magnetic resonance imaging (MRI) scan

MRI scans are used less often than CT scans in people with kidney cancer. They may be done in cases where CT scans aren’t practical, such as if a person can’t have the CT contrast dye because they have an allergy to it or they don’t have good kidney function. MRI scans may also be done if there’s a chance that the cancer has grown into major blood vessels in the abdomen (like the inferior vena cava), because they provide a better picture of blood vessels than CT scans. Finally, they may be used to look at abnormal areas in the brain and spinal cord that might be due to cancer spread.

Ultrasound

Ultrasound can help find a kidney mass and show if it is solid or filled with fluid (kidney tumors are more likely to be solid). Different echo patterns also can help doctors tell some types of benign and malignant kidney tumors from one another.

If a kidney biopsy is needed, this test can also be used to guide a biopsy needle into the mass to obtain a sample.

Positron emission tomography (PET) scan

A PET scan uses a form of radioactive sugar that is put into the blood. Body cells take in different amounts of the sugar, depending on how fast they are growing. Cancer cells, which grow quickly, are more likely to take up larger amounts of the sugar than normal cells. A special camera is used to create a picture of areas of radioactivity in the body. The picture from a PET scan is not as detailed as a CT or MRI scan, but it provides helpful information about whether abnormal areas seen on these other tests are likely to be cancer or not. This scan can be useful in seeing if the cancer has spread to lymph nodes near the kidney. PET scans can also be useful if your doctor thinks the cancer may have spread but doesn’t know where.

Special machines can perform both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity (suggesting an area of cancer) on the PET scan with the more detailed picture of that area on the CT.

Still, PET and PET/CT scans are not a standard part of the work-up for kidney cancers.

Intravenous pyelogram

An intravenous pyelogram (IVP) is an x-ray of the urinary system taken after a special dye is injected into a vein. The kidneys remove the dye from the bloodstream and it then concentrates in the ureters and bladder. An IVP can help find abnormalities of the renal pelvis and ureter, such as cancer, but this test is not often used when kidney cancer is suspected.

Angiography

Angiography is an x-ray test for looking at blood vessels. A contrast dye is injected into the renal artery, and the dye outlines the blood vessels. X-rays are taken to identify and map the blood vessels that supply a kidney tumor. This type of contrast dye though, is not the same as the one used for an IVP.

This test can help in planning surgery for some patients. Angiography can also help diagnose renal cancers since the blood vessels usually have a special appearance with this test.

Angiography can often be done as a part of a CT or MRI scan, instead of as a separate x-ray test. This means less contrast dye is used, which is helpful since the dye can damage kidney function further if it is given to people whose kidneys aren’t working well.

Chest x-ray

An x-ray may be done after kidney cancer has been diagnosed to see if cancer has spread to the lungs.

Bone scan

A bone scan can help show if a cancer has spread to your bones. It might be done if there is reason to think the cancer might have spread to the bones (because of symptoms such as bone pain or blood test results showing an increased calcium level). PET scans can usually show the spread of cancer to bones as well, so if you’ve had a PET scan you might not need a bone scan.

Kidney biopsy

Unlike with most other types of cancer, biopsies are not often used to diagnose kidney tumors. Imaging tests usually provide enough information for a surgeon to decide if an operation is needed. The diagnosis is then confirmed when part of the kidney that was removed is looked at in the lab.

However, a biopsy is sometimes done to get a small sample of tissue from an area that may be cancer when the imaging tests are not clear enough to permit surgery. Biopsy may also be done to confirm cancer if a person might not be treated with surgery, such as with small tumors that will be watched and not treated, or when other treatments are being considered.

Fine needle aspiration (FNA) and needle core biopsy  are 2 types of kidney biopsies that may be done.

In cases where the doctors think kidney cancer might have spread to other sites, they may take a biopsy of the metastatic site instead of the kidney.

Biopsy results

The biopsy samples are sent to a lab, where they are looked at by a pathologist, a doctor who specializes in diagnosing diseases with lab tests. If kidney cancer is found, an important feature that is evaluated is the grade, specifically called Fuhrman grade.

The Fuhrman grade is found by looking at kidney cancer cells (taken during a biopsy or during surgery) in a lab. Many doctors use it to describe how quickly the cancer is likely to grow and spread. The grade is based on how closely the cancer cells look like those of normal kidney cells. Renal cell cancers are usually graded on a scale of 1 through 4. Grade 1 renal cell cancers have cells that look a lot like normal kidney cells. These cancers usually grow and spread slowly and tend to have a good prognosis (outlook). At the other extreme, grade 4 renal cell cancer looks quite different from normal kidney cells. These cancers have a worse prognosis.

Although the cell type and grade can sometimes help predict prognosis (outlook), the cancer’s stage is by far the best predictor of survival. The stage describes the cancer’s size and how far it has spread beyond the kidney. Staging is explained in Kidney Cancer Stages.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: August 1, 2017 Last Revised: August 1, 2017

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