Key takeaways
- Blood tests that screen for many types of cancer are still in development and not routinely available
- While routine blood tests cannot diagnose cancer, they can indicate some abnormalities that might require further investigation
- If your GP suspects blood, ovarian or prostate cancer, you might have a specific blood test
- NHS cervical, breast and bowel screening tests do not include blood testing
Scientists are currently developing blood tests that can screen for many types of cancer at once. But for now, blood tests are mostly used to detect health conditions that may include cancers and need to be considered alongside other tests. In this article, Lead Cancer Nurse Specialist Rachel Rawson offers straightforward information about what blood tests can and can’t do when it comes to cancer, as well as information about screening programmes.
Can a routine blood test diagnose cancer?
Your GP might order a routine blood test to help check your general health, check numbers of blood cells or help diagnose a specific health issue. A routine blood test can not diagnose cancer. Rather, a routine blood test can show abnormalities that might be a sign of cancer – things like a significantly abnormal blood count or high calcium levels. If your blood test results indicate one of these things, your GP will consider the results along with any other symptoms and your overall cancer risk (including age, family history, smoking, etc.) before deciding next steps. Abnormal blood tests can usually be an indication of many health problems, not just cancer.
If your blood test results are normal, that is often very reassuring. However, your GP might be concerned about other symptoms that need further investigation before they can completely rule out cancer. If your symptoms change, get worse or you feel worried, return to your GP.
Are there specific blood tests to diagnose some cancers?
There are various blood tests that can help in the diagnosis of some cancers and if your GP is concerned they might order these tests along with other investigations. For example:
- Blood cancers
Blood tests can help diagnose blood cancers including Leukaemia, Lymphoma and Myeloma. - Ovarian cancer
If there are problems with your ovaries, you might be offered a CA-125 blood test. If your doctor is worried about your blood test results, you may need a scan. - Prostate cancer
A prostate-specific antigen (PSA) test is a blood test commonly used to rule out prostate cancer. Your PSA level might be raised for reasons other than prostate cancer, such as an infection of either the prostate or urinary tract. However, if your blood test shows high levels of PSA, you may need a scan or biopsy to exclude prostate cancer.
Are blood tests included in cancer screening?
Screening tests are used to find cancer or cell abnormalities that might develop into cancer in people who have no symptoms. Regular screening gives you the best chance of finding cell abnormalities and cancer early. In the UK, the NHS offers three screening tests – cervical, breast and bowel. None of these screening tests involves a blood test.
Cervical screening tests a small sample of cells taken from the neck of the womb, breast screening uses a breast X-ray called a mammogram and bowel screening tests a small sample of poo. You will automatically be invited for screening when you reach an eligible age, or if you have an increased risk of these cancers.
While we have ensured that every article is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns, please talk to one of our healthcare professionals or your primary healthcare team.
References:
‘Blood tests for cancer diagnosis – myths vs facts,’ Genesis Care, January 2023, https://www.genesiscare.com/uk/patient-support/blog/blood-tests-for-cancer-diagnosis-myths-vs-facts