Diagnostic tests for cancer

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Diagnostic tests help the health-care team determine if you have cancer and what type of cancer you may have. Learn more about the different types of tests, consent and waiting for the test results.

Key points

  • Diagnostic tests help the health-care team to make a diagnosis and learn additional information about the cancer.
  • Tests include blood tests, scans, biopsies, bone marrow tests and lumbar punctures.
  • Some tests will be done more than once as you go through treatment to see how the cancer is responding to treatment.

What are diagnostic tests?

Diagnostic tests are tests that doctors use to help them make a diagnosis. Tests give your health-care team special information about the cancer they cannot learn from a physical examination. Some tests you might have during cancer diagnosis include:

All of these tests are described in the following sections.

Tests do not end after diagnosis. Your health-care team will carry out more tests to see how your cancer and your body are doing during and after cancer treatment. You will need to have many of these tests more than once. Some tests, such as blood tests, need to be done pretty often.

It may seem like a lot of tests, but remember you need the tests so you can get the best treatment. Test results help your health-care team monitor how your cancer is responding and the effects of the treatment on the rest of your body.


Before some tests, such as a lumbar puncture, biopsy or bone marrow test, you and/or your parents will be asked to sign a consent form. Signing a consent form gives the doctors permission to do the test. For more information, check out the page on consent.

Waiting for test results can be really stressful

Some test results take longer than others. Talking about how you feel with your health-care team, your family or your friends can help you cope. It may also help your health-care team better understand how to help and support you.

Understanding a bit about tests can help make them a little easier to deal with. Your best source of information about any test or scan is your health-care team. Here is a list of questions that you or your parents can ask your health-care team to help you understand more about tests.

  • Why do I need to have this test?
  • What will happen during the test?
  • What do I need to do to get ready for the test?
  • If the test is painful, are there medicines or other things that will help with the pain?
  • What are the risks that come with this test?
  • What will happen after the test?
  • What will the results mean for me?

Remember, the people on your health-care team are there to answer your questions. Ask them lots of questions. They want to help you understand! Some people like to write down their questions as they think of them, to make sure they remember all of their questions when they meet with their health-care team.

Last updated: September 3rd 2019