Blood Test For Cancer? Complete Blood Count And Cancer

Complete Blood count And Cancer

There is no particular test to diagnose cancer, but laboratory tests like cancer blood counts may give the physician important information about your condition. A complete blood count or CBC is a test measuring the number of red cells, white cells, and platelets in your blood.

Except for blood cancer, the blood tests might not precisely indicate the presence of cancer but may provide a clue to your doctor about what is going on inside the body.

Complete Blood Count:

A complete blood count test is a standard laboratory blood test to measure the quality and number of red blood cells, platelets, and white blood cells.

Blood Count Measures:

A complete blood count test measures the amount of blood cells circulating in the bloodstream. It accurately measures the following types of cell counts in the human body:

Red Blood Cells (RBCs):

Red blood cells are the cells carrying oxygen throughout the human body. They are also known as erythrocytes.


Platelets prevent bleeding by the formation of blood clots. A platelet count measures the amount or number of platelets.

White Blood Cells (WBCs)

White blood cells are also known as leukocytes. Their function is to safeguard the body from infections by bacteria and viruses. WBCs are responsible for fighting cancer cells.

Why is complete Cancer blood count done?

Your doctor might order you a complete blood count test for the following reasons:

  • A full picture of blood count gives general information on the health of a person
  • It helps to assess if the blood-forming organs (bone marrow) functions normally
  • It helps in the diagnosis of blood cancers like leukemia and lymphoma
  • To find if cancer might have metastasized (spread to other areas)
  • Determine the body’s ability to cope with cancer treatment
  • To verify anemia or any other infection

What the results conclude:

Low Red Blood Cells

If your hemoglobin is low, your health care professional may say you are anemic. It can make you feel fatigued and short of breath. Cancers that include the bone marrow may worsen anemia. 

Following are the factors of high and low RBC counts:

Low White Blood Cells:

A low white blood cell count (leukopenia) exposes your body to infection. If an infection develops, your body may be unable to fight it off. Some cancer treatments like chemotherapy may also decrease white blood cells in the body.

Low Platelet Count: 

Platelets help clot the blood, to stop injuries from bleeding. A low platelet count might result in abnormal bleeding, such as bleeding gums and nosebleeds. 


A complete blood count is a regular and standard laboratory test to investigate the general health of a patient.