What is a complete blood count?

A total blood count (CBC) is a test that counts the cells that make up your blood: red blood cells, white blood cells, and platelets. Your primary care physician might arrange a CBC as a component of a standard exam or to:

Check for weakness, a condition that makes you have less red blood cells than expected See whether you have another medical problem or to make sense of side effects like shortcoming, fever, swelling, or feeling tired
Watch out for a blood condition perceive how prescriptions, ailments, or medicines like chemotherapy are influencing your blood.

How Is a CBC Done?

If the CBC is the main blood test you're having, you can eat and drink like you generally would. Your piece of the test is basic and requires only a couple of moments. A medical attendant or lab tech will take an example of blood by placing a needle into a vein in your arm. A short time later, you can leave and return to your everyday practice. They'll send the blood to a lab for survey.

What Does a CBC Measure?

White blood cells (WBCs) - These help your body fight germs. If you have too many of them, it could be a sign of inflammation, infection, a medical reaction, or another health condition. If it’s low, you could be at a higher risk for infection. A medication, a viral infection, or a bone marrow disease could also cause a low count.
Red blood cells (RBC) - These deliver oxygen throughout your body. They also help carry carbon dioxide. If your RBC count is too low, you may have anemia or another condition.
Hemoglobin (Hb or Hgb) - This is the protein in your blood that holds oxygen.
Hematocrit (Hct) - This test tells how much of your blood is made up of red blood cells. A low score may be a sign that you don’t have enough iron, the mineral that helps your body make red blood cells. A high score could mean you’re dehydrated or have another condition.
Mean corpuscular volume (MCV) - This is the average size of your red blood cells. If they’re bigger than usual, your MCV will be higher. That could happen if you have low vitamin B12 or folate levels. If your red blood cells are smaller, you could have a type of anemia.
Platelets - These help your blood clot.

CBC Results

In general, the reference ranges are:

White blood cells: 4,500 to 11,000 cells per microliter (cells/mcL)
Red blood cells: 4.5 million to 5.9 million cells/mcL for men; 4.1 million to 5.1 million cells/mcL for women
Hemoglobin: 14 to 17.5 grams per deciliter (gm/dL) for men; 12.3 to 15.3 gm/dL for women
Hematocrit: 41.5% to 50.4% for men; 35.9% to 44.6% for women
Mean corpuscular volume: 80 to 96
Platelets: 150,000 to 450,000 platelets/mcL

What do the results mean?

A CBC counts the cells and measures the levels of different substances in your blood. There are many reasons your levels may fall outside the normal range. For instance:

Abnormal red blood cell, hemoglobin, or hematocrit levels may indicate anemia, iron deficiency, or heart disease.
Low white cell count may indicate an autoimmune disorder, bone marrow disorder, or cancer.
High white cell count may indicate an infection or reaction to medication.
If any of your levels are abnormal, it does not necessarily indicate a medical problem needing treatment. Diet, activity level, medications, a women's menstrual cycle, and other considerations can affect the results.