Complete Blood Count (CBC)

 

The CBC is used as a broad screening test to check for such disorders as anemia, infection, and many other diseases. It is actually a panel of tests that examines different parts of the blood.

• Red blood cells: The CBC's measurements of red blood cell (RBC) count, hemoglobin (the oxygen-carrying protein in RBCs), and mean (red) cell volume (MCV) provides information about the RBCs, which carry oxygen from the lungs to the rest of the body. These measurements are usually done to test for anemia, a common condition that occurs when the body has insufficient red blood cells.
• White blood cells: The white blood cell (WBC) count measures the number of WBCs (also called leukocytes) in the blood. WBCs, which help the body fight infection, are bigger than red blood cells and there are far fewer of them in the bloodstream. An abnormal WBC count may indicate an infection, inflammation, or other stress in the body.
• Platelets: The smallest blood cells, platelets play an important role in blood clotting and the prevention of bleeding. When a blood vessel is damaged or cut, platelets clump together and plug the hole until the blood clots. If the platelet count is too low, a person can be in danger of bleeding in any part of the body.

Specimen: Venous blood

Pretest: obtain syringe, tourniquet, vial with appropriate anticoagulant
Intratest: Cubital vein commonly used for venipuncture
Post-test: direct pressure and observe for bleeding, label vial

 

Normal Values For CBC:
RBC (M) 4.7-6.1/ (F) 4.2-5.4
Hgb (M) 14-18 / (F) 12-16 mg/dl
Hct (M) 42-52 / (F) 33-47 %
WBC 5-10,000
Differential count
Neutrophils- 55- 70%
Lymphocytes- 20-40%
Monocytes- 2-5%
Eosinophils- 1-4%
Platelets 150,000-400,000