Complete Blood Count (CBC) Test

CBC Tests at Wellstar

The complete blood count test measures the levels of the three basic blood cells: red blood cells, white blood cells, and blood platelets.

Before the procedure

Your Wellstar physician may order a CBC:

• As part of a physical examination
• To diagnose a specific disease or condition, including anemia or infection
• To monitor a medical condition
• To monitor a medical treatment that might affect your blood counts

No special preparations are required before the procedure.

During the procedure

• Blood is typically drawn from a vein inside the elbow.
• The site will be cleaned with an antiseptic.
• Your healthcare provider will wrap an elastic band around your upper arm to make your vein swell with blood.
• Your healthcare provider will carefully insert a needle in to the vein.
• The blood will be drawn in to an airtight vial or tube attached to the needle.
• The elastic band will be removed from your arm.
• A band-aid will be applied to the puncture site to stop the bleeding.

Once in the lab, the test is an automated count of the following cells in the blood:

• White blood cells (WBC)
• Red blood cells (RBC)
• Hemoglobin content (Hgb)
• Hematocrit (Hct)
• Mean corpuscular volume (MCV)
• Mean corpuscular hemoglobin (MCH)
• Mean corpuscular hemoglobin concentration (MCHC)
• Platelet count and volume

After the procedure

You will be able to return to your normal activities immediately after having your blood taken.

Your blood will be sent to Wellstar’s Laboratory Services for the automated count. Your Wellstar physician will go over the results with you.

Normal results are:

• RBC count (varies with altitude):
  • Male: 4.7 t6.1 million cells/mcL
  • Female: 4.2 t5.4 million cells/mcL
  • WBC count: 4,500 t10,000 cells/mcL
• Hematocrit (varies with altitude):
  • Male: 40.7 t50.3 %
  • Female: 36.1 t44.3 %
• Hemoglobin (varies with altitude):
  • Male: 13.8 t17.2 gm/dL
  • Female: 12.1 t15.1 gm/dL

(cells/mcL = cells per microliter; gm/dL = grams per deciliter)

Increases or decreases in your blood count can mean the following, though they don’t have to mean anything. Talk to your physician about your results.

High numbers of RBC's, high hemoglobin or a high hematocrit may be due to:

• Dehydration (such as from severe diarrhea)
• Kidney disease with high erythropoietin production

Low oxygen level in the blood, which could indicate:

• Congenital heart disease
• Corpulmonale
• Pulmonary fibrosis
• Polycythemia vera
• Smoking

Low numbers of RBC's, low hemoglobin or low hematocrit indicates anemia, which can result from:

• Lupus Erythematosus
• Rheumatoid arthritis
• Blood loss (hemorrhage)
• Bone marrow failure
• Erythropoietin deficiency
• Hemolysis (red blood cell destruction)
• Leukemia
• Malnutrition
• Multiple myeloma

A lower-than-normal white blood cell count is called leukopenia. A decreased WBC count may be due to:

• Autoimmune/collagen-vascular diseases (such as systemic lupus erythematosus)
• Bone marrow problem
• Cancer
• Disease of the liver or spleen
• Certain medications

High numbers of WBC's is called leukocytosis. It can result from:

• Infectious diseases
• Inflammatory disease (such as rheumatoid arthritis or allergy)
• Leukemia
• Severe emotional or physical stress
• Tissue damage (such as burns)
• Reaction to medication