What is the complete blood count test (CBC) ?

CBC

What is the complete blood count test (CBC)?

A complete blood count (CBC) is a blood test used to evaluate your overall health and detect a wide range of disorders, including anemia, infection and leukemia.

 (CBC) is one of the most commonly ordered blood tests. The complete blood count is the calculation of the cellular (formed elements) of blood. These calculations are generally determined by special machines that analyze the different components of blood in less than a minute.

A complete blood count test measures several components and features of your blood, including:

ý  Red blood cells, which carry oxygen

ý  White blood cells, which fight infection

ý  Hemoglobin, the oxygen-carrying protein in red blood cells

ý  Hematocrit, the proportion of red blood cells to the fluid component, or plasma, in your blood

ý  Platelets, which help with blood clotting

The CBC test also provides information about the following measurements:

ý  Average red blood cell size (MCV(

ý  Hemoglobin amount per red blood cell (MCH)

ý  The amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC)

How is the complete blood count test (CBC) done?

The complete blood count (CBC) test is performed by obtaining a few milliliters (one to two teaspoons) of blood sample directly from the patient. It can be done in many settings including the doctor's office, laboratories, and hospitals. The skin is wiped clean with an alcohol pad, and a needle is inserted through the area of cleansed skin into to patient's vein (one that can be visualized from the skin.) The blood is pulled from the needle by a syringe or by a connection to a special vacuumed vial where it is collected. This sample is taken to the laboratory for analysis.

Medical uses

Complete blood counts are done to monitor overall health, to screen for some diseases, to confirm a diagnosis of some medical conditions, to monitor a medical condition, and to monitor changes in the body caused by medical treatments.

For patients who need blood transfusion, a blood count may be used to get data which would help plan an amount of treatment. In such cases, the person should have only one blood count for the day, and the transfusion of red blood cells or platelets should be planned based on that. Multiple blood draws and counts throughout the day are an excessive use of phlebotomy and can lead to unnecessary additional transfusions, and the extra unnecessary treatment would be outside of medical guidelines.

Result

see table