A physician may order complete blood count (CBC) for many reasons. Often, it is ordered as part of a routine checkup or as part of the hospital admission process. It can give a clue to your general health or expose signs of a wide array of illnesses. Some CBC tests are ordered in sequence, such as weekly, to ensure good health is returning to you after a period of illness or trauma. When evaluating your CBC results, the medical personnel must compare your test results against normal values to learn if you may have a health problem.
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Red Blood Cells
A complete blood count looks at the number of red blood cells (RBCs) present in a small amount of your blood. According to the U.S. National Library of Medicine, the normal value for a female is 4.2 to 5.4 million red blood cells per microliter. For males, the normal value is slightly higher at 4.7 to 6.1 million red blood cells per microliter. Normal values may vary slightly depending on altitude. For all figures listed, normal results may vary slightly depending on which laboratory is used. Red blood cells take oxygen to the body and perform other vital functions.
White Blood Cells
Next, the CBC examines your white blood cells. The average person has fewer white blood cells than red ones, with the normal white blood cell count being 4,500 to 10,000 white blood cells per microliter. White blood cells help fight infection and perform other duties for the body.
Most CBC tests evaluate the number of platelets in a small sample of blood. They are dwarfed by the larger red blood cells and white blood cells. Normal values range from 150,000 to 400,000 cells per microliter. Platelets are a vital component for the clotting of blood.
Hemoglobin is the part of red blood cells that gives them their color. It is responsible for transporting oxygen to all the cells of the body. A normal hemoglobin level for females is 12.1 to 15.1g per deciliter, while a normal level for men is 13.8 to 17.2g per deciliter. The normal values vary slightly according to altitude.
A device called a hematocrit is used to determine the percentage of your blood volume that is packed with red blood cells. For males, a normal result is 40.7 percent to 50.3 percent. For females, a normal result is a little lower, with a range between 36.1 percent and 44.3 percent. These normal values will vary slightly according to altitude.
Other Red Blood Cell Values
A complete blood count includes a mean corpuscular volume (MCV) level, with 80 to 95 femtoliters being normal. Also included is a mean corpuscular hemoglobin (MCH) level with a normal value of 27 to 31 picograms per cell and a mean corpuscular hemoglobin concentration (MCHC) level with normals being 32 to 36g per deciliter. These tests are all related to the red blood cells.