In its early stages, kidney cancer often has no symptoms. In fact, abnormalities in routine blood tests may be the first sign of a problem with your kidneys.

However, a blood test cannot diagnose kidney cancer. Rather, a blood test can give doctors important information about how your kidneys are functioning.

Blood tests help your doctor determine what additional tests you may need. They are an important part of the diagnostic process.

For example, after blood work, your doctor might order imaging tests to look for additional signs of kidney cancer, or they might move in a different direction to look for the cause of your symptoms.

So, although a blood test alone doesn’t diagnose cancer, your blood test results are a very important part of the process.

A blood test is not enough on its own to confirm a diagnosis of kidney cancer. However, certain results could indicate kidney problems and a possible need for further testing.

Standard blood tests are often done during periodic health exams. Certain abnormalities could flag the potential for cancer.

There are a few types of blood tests that might be used in an initial cancer screening. These include:

  • Complete blood count (CBC). A CBC is a test that measures the levels of several types of cells in your body. People with kidney cancer often have abnormal levels of important cells.
  • Basic metabolic panel. This test checks for levels of specific compounds in your blood. For kidney cancer, your doctor will be interested in looking at liver enzymes, calcium levels, blood urea nitrogen, and glomerular filtration rate.
  • Serum creatinine. This test can help rule out kidney function issues that may be causing your symptoms. It measures how well your kidneys are filtering your blood. It can be a good indicator of overall kidney health.

Blood test results can indicate your kidneys aren’t working correctly and that more tests need to be done. Results that might prompt further testing include:

  • CBC. It’s common for people with kidney cancer to have fewer red blood cells than is considered to be healthy (anemia) or, rarely, more red blood cells than is considered to be healthy (polycythemia) due to abnormal kidney function. Either of these results indicates the need for further testing.
  • Blood chemistry test. People with kidney cancer often have high levels of liver enzymes or calcium in their blood due to reduced kidney function. You’ll need additional tests if your blood chemistry test shows high levels of these chemicals.

Blood tests are not enough to diagnose kidney cancer. If your doctor suspects kidney cancer, you’ll likely have a range of other tests to confirm your diagnosis. This often includes:

  • CT scan. A CT scan uses multiple X-ray images to create detailed images of your kidneys so doctors can look for tumors and other issues.
  • MRI. An MRI uses magnetic imaging to create images of your kidney to check the size, shape, and location of any tumors.
  • Ultrasound. An ultrasound uses sound waves to create images of your kidneys. It can help locate tumors and whether they are benign or cancerous.
  • Bone scan. A bone scan can be done to see the inside of your bones. Your doctor might do this test if they suspect cancer has spread to your bones.
  • Biopsy. During a biopsy, a small piece of your kidney is removed with a needle so it can be tested in a lab. Biopsy results can confirm cancer and help diagnose the stage of the tumor.
  • Renal angiography. This test helps your doctor see the blood supply to your kidneys in detail. Blood supply to a tumor, if present, is also able to be seen here.
  • Intravenous pyelogram. This test requires dye to be injected into a vein so the kidneys are more visible via X-ray. This is another way an obstruction or tumor can be detected.

Often, there are no signs or symptoms of kidney cancer, especially in its early stages.

Kidney cancer is often found during routine blood work or testing for other concerns. When symptoms are present, they can look like symptoms of less serious conditions, like bladder infections or kidney stones.

Symptoms of kidney cancer may include:

It’s best to talk with a doctor if you have any signs and symptoms that make you suspect cancer.

Although most symptoms of kidney cancer are more likely to be symptoms of a much less serious condition, the survival rates and outlook for people with kidney cancer are better when the cancer is found and treated in the early stages.

It’s a good idea to make a doctor’s appointment if you’ve had any concerning symptoms for more than 2 weeks.

Blood tests can’t confirm kidney cancer, but they can help indicate problems with kidney function. They’re often one of the first tests a doctor will order if kidney cancer is suspected.

Blood tests can look at the levels of cells and chemicals in your blood and be the first step in an accurate diagnosis.

Additional tests for kidney cancer include imaging tests and biopsies. With these tests, doctors can confirm a diagnosis, see tumors, determine the spread of cancer, and stage the tumor. Diagnosis is the first step to getting treatment for kidney cancer.