November 4, 2023


Can Cancer Be Detected by Blood Test?

Yes, some types of cancer can be detected through blood tests that look for tumor markers or other changes in the blood. Blood tests can be an effective way to screen for cancers like leukemia, lymphoma, ovarian, prostate, testicular, pancreatic, liver, colon, lung, and breast cancer. The accuracy varies based on the type of cancer and test used.

Types of Cancer That Can Be Detected by Blood Test

Some of the types of cancer that can be detected by blood tests include:

  • Leukemia
  • Lymphoma
  • Multiple myeloma
  • Prostate cancer
  • Ovarian cancer
  • Testicular cancer
  • Pancreatic cancer
  • Liver cancer
  • Colon cancer
  • Lung cancer
  • Breast cancer

How Accurate Are Blood Tests for Cancer Detection?

The accuracy of blood tests for cancer detection varies depending on the type of cancer and the specific test being used. For example, the prostate-specific antigen (PSA) test is a very good screening test for prostate cancer, but it is not specific for cancer, meaning that it can also be elevated in men with benign prostatic hyperplasia (BPH) or other non-cancerous conditions.

When Should I Get a Blood Test for Cancer Detection?

If you have any of the following cancer symptoms, you should talk to your doctor about getting a blood test for cancer detection:

  • Unexplained weight loss
  • Fatigue
  • Fever
  • Night sweats
  • Pain
  • Lumps
  • Bleeding or unusual discharge
  • Changes in bowel or bladder habits

If you have a family history of cancer or other risk factors for cancer, your doctor may also recommend that you get regular blood tests for cancer detection.

What Happens if My Blood Test Results Are Abnormal?

If your blood test results are abnormal, your doctor will likely order additional tests to confirm the diagnosis. These tests may include imaging tests, such as a CT scan or MRI, or a biopsy, which is a procedure to remove a small sample of tissue for examination under a microscope.

Cancer Medicine and Blood Tests

Blood tests can also be used to monitor the response to cancer treatment and to detect cancer recurrence. For example, cancer patients may have regular blood tests to measure tumor marker levels. If tumor marker levels start to rise, it may be a sign that the cancer is progressing or has recurred.

Cancer Medicine and Early Detection

Early detection is crucial for successful cancer treatment. By detecting cancer early, doctors can start treatment sooner and improve the chances of a cure. Blood tests can play a vital role in early cancer detection by identifying cancer cells or tumor markers in the blood before symptoms develop.

Cancer Medicine and Personalized Treatment

Anti cancer medicine is becoming increasingly personalized, with treatments tailored to the specific genetic makeup of each patient’s cancer. Blood tests can be used to identify genetic mutations that drive cancer growth and progression. This information can then be used to select targeted therapies that are most likely to fbe effective against the patient’s cancer.

What Blood Test Detects Cancer Early?

A blood test called the multi-cancer early detection (MCED) test is a new type of blood test that can detect early signs of cancer in over 50 different types of cancer.

The test looks for circulating tumor DNA (ctDNA), which are small fragments of DNA that are released into the bloodstream by cancer cells.

How Accurate Is MCED in Cancer Detection? 

The accuracy of MCED tests in cancer detection is still being studied. However, early clinical trials have shown that MCED tests can be very accurate in detecting cancer, especially early-stage cancer.

For example, one study found that the Galleri MCED test detected cancer in over 50% of people who had stage I or II cancer, and in over 70% of people who had stage III or IV cancer.

What Should I Do If My Blood Test Indicates a Potential Cancer Risk?

If your blood test indicates a potential cancer risk, the first thing you should do is talk to your doctor. Your doctor will want to review your medical history and risk factors and may order additional tests to confirm the results of the blood test.

Depending on the results of the additional tests, your doctor may recommend that you see a specialist, such as an oncologist or a hematologist. The specialist will work with you to develop a plan to monitor your condition and manage your risk of cancer.

Here are some things you can do to manage your risk of cancer:

  • Quit smoking. Smoking is a leading cause of cancer, so quitting smoking is one of the best things you can do to reduce your risk of cancer.
  • Eat a healthy diet. Eating a healthy diet that is rich in fruits, vegetables, and whole grains can help to reduce your risk of cancer.
  • Exercise regularly. Exercise can help to reduce your risk of cancer by maintaining a healthy weight and reducing inflammation.
  • Get regular cancer screenings. Cancer screenings can help to detect cancer early when it is most treatable.

Are There Different Types of Blood Tests for Different Types of Cancer?

Yes, there are different types of blood tests for different types of cancer. Some blood tests are designed to detect specific cancer markers, which are substances that are produced by cancer cells or by the body in response to cancer.

Other blood tests are designed to look for general changes in the blood that may indicate cancer, such as changes in the number of white blood cells or platelets.

Here are some examples of blood tests for different types of cancer:

  • Complete blood count (CBC): A CBC is a type of blood test that measures the number of different types of blood cells, including white blood cells, red blood cells, and platelets. Changes in the number of blood cells may indicate cancer, such as leukemia or lymphoma.
  • Blood chemistry tests: Blood chemistry tests measure the levels of various chemicals in the blood, such as liver enzymes, kidney function tests, and electrolytes. Changes in the levels of these chemicals may indicate cancer, such as liver cancer or kidney cancer.
  • Circulating tumor DNA (ctDNA) tests: ctDNA tests are a new type of blood test that can detect cancer cells in the blood. ctDNA is released into the bloodstream when cancer cells die. ctDNA tests are still under development, but they have the potential to detect cancer early when it is most treatable.

Can a CBC detect cancer?

Yes, a CBC (complete blood count) can detect cancer, but it is not a definitive test. A CBC measures the number of different types of blood cells in your blood, including red blood cells, white blood cells, and platelets. Changes in the number of blood cells may indicate cancer, such as leukemia or lymphoma.

However, a CBC can also be abnormal for other reasons, such as infection, inflammation, or anemia. Therefore, a CBC by itself cannot diagnose cancer. If your CBC is abnormal, your doctor may order other tests to confirm the diagnosis.

Can You Have Cancer with Normal WBC?

Yes, it is possible to have cancer with a normal white blood cell (WBC) count. Some types of cancer, such as solid tumors, can cause WBC counts to remain normal.

WBCs are part of the immune system and help to fight infection. When the body is fighting an infection, the number of WBCs in the blood increases. However, cancer cells can sometimes interfere with the production of WBCs, which can lead to a low WBC count.


Blood tests are an important tool for cancer detection, monitoring, and treatment. By understanding how blood tests are used in cancer medicine, patients can make informed decisions about their care and improve their chances of a positive outcome.

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