Complete Blood Count (CBC)

A CBC is made up of measurements of specific blood components. The
following are important parts of a CBC.

WBC (White Blood Cells)
White blood cells are the infection fighters, like little pac-men they gobble up invading germs. Normal values differ between laboratories, but generally 4,000 to 10,000 cells per cubic milliliter (cmm). It may also be expressed as a smaller number, 4-10. An abnormally high number indicates the presence of infection or may be caused by certain medications like steroids. Certain blood diseases and some autoimmune diseases may cause a low result. DMARD therapy can also lower the WBC.

RBC (Red Blood Count)
Red blood cells give the blood its color. They carry oxygen from the lungs to the rest of the body. Normal values are usually between 4.2 – 5.9 million cells/cmm. Many times this is expressed simply as 4.2-5.9.

Hgb (Hemoglobin)
Hemoglobin is the protein molecule within the red blood cells. Normal range for hemoglobin is different between the sexes and is approximately 13 – 18 grams per deciliter for men and 12 – 16 for women.

Hct (Hematocrit)
The hematocrit is the ratio of volume to red blood cells to the volume of whole blood. Normal range for hematocrit is different between the sexes and is approximately 45 – 52% for men and 37 – 48% for women.

A lower than normal result in RBC’s, Hct and Hgb indicates anemia. The medications or the disease itself can cause anemia in those with inflammatory arthritis. A sudden drop in the numbers may indicate active bleeding and is cause for concern.

PLT (Platelet Count)
Platelets are involved in blood clotting and bleeding. Normal range varies between laboratories but is usually 150,000 – 400,000/ cmm. This result may also be expressed as simple numbers, 150-400. An increase in platelet count is can be seen with malignancy, blood diseases, or rheumatoid arthritis. Low counts may be seen in blood diseases, infections, and as the result of certain medications.

MCV ( Mean Corpuscular Volume)
The MCV is the average volume of a red cell. This is a calculated value derived from the hematocrit and red cell count. Normal range is 86 – 98 femtoliters. If elevated, it may indicate anemia from vitamin deficiency such as vitamin B12 or folic acid. If it is below normal it usually indicates anemia from iron deficiency.

For more information:

& Marrow Test Values

Central – Lab Tests, What They Mean

Yale University School of Medicine, Patient’s Guide to Medical Tests