Can a blood test detect Cancer?

When someone gets diagnosed with cancer, a thought might cross their mind — if I had cancer, why did my previous blood reports not detect it? While the idea of a straightforward diagnostic tool sounds promising, the reality is far from simple. Read on to know can a blood test detect cancer?

Blood Test which can detect Cancer

Blood tests, which can diagnose certain types of cancer, include:

• Complete Blood Count (CBC)

A CBC test measures different types of blood cells circulating in your bloodstream, including platelets, white blood cells, and red blood cells. This test helps doctors diagnose cancer or detect if cancer has spread. However, a CBC can detect only certain types of cancers, such as leukaemia, multiple myeloma, Hodgkin lymphoma, and non-Hodgkin’s lymphoma.

• Blood chemistry

Blood chemistry can’t detect cancer but can indicate some signals that need further testing.

• Tumour markers

These are proteins and chemicals found in your blood. If cancer cells are present in your body, this test will show high levels of tumour markers and may be a sign of prostate cancer or other types of cancer.

• ctDNA

This is a new type of blood test which looks for circulating tumour cells. These cells have separated from a tumour and are moving in your bloodstream, indicating the spread of cancer in your body. It can help monitor certain types of carcinoma like prostate, breast, and colorectal cancers.

What Blood Tests Can Tell Your Physicians

Most cancers cannot be diagnosed with routine blood tests like CBC, blood chemistry, and tumour markers. A CBC test can help in detecting only blood cancers - leukaemia, multiple myeloma, Hodgkin’s lymphoma, and non-Hodgkin’s lymphoma.

Blood chemistry is another common test that examines the various chemicals present in your body, including proteins, electrolytes, cholesterol, and blood glucose. Although blood chemistry cannot detect cancers, it can indicate abnormalities and warning signs for which your doctor may recommend further testing.

Tumour markers test is done to detect chemicals and proteins present in your blood. If the tumour markers are more than the normal range, it is indicative of cancer. However, this blood test is mostly done to monitor therapy effects.