Complete blood count; Anemia - CBC
RBCs transport hemoglobin which, in turn, carries oxygen. The amount of oxygen received by body tissues depends on the amount and function of RBCs and hemoglobin.
WBCs are mediators of inflammation and the immune response. There are various types of WBCs that normally appear in the blood:
A complete blood count (CBC) test measures the following:
The CBC test also provides information about the following measurements:
The platelet count is also most often included in the CBC.
A blood sample is needed.
When the needle is inserted to draw blood, you may feel moderate pain. Some people feel only a prick or stinging. Afterward there may be some throbbing or slight bruising. This soon goes away.
There is no special preparation needed.
Blood counts may vary with altitude. In general, normal results are:
Red blood cell indices:
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
High RBC, hemoglobin, or hematocrit may be due to:
Low RBC, hemoglobin, or hematacrit is a sign of anemia, which can result from:
A lower than normal white blood cell count is called leukopenia. A decreased WBC count may be due to:
A high WBC count is called leukocytosis. It can result from:
A high platelet count may be due to:
A low platelet count may be due to:
A CBC is a commonly performed lab test. It can be used to detect or monitor many different health conditions. Your health care provider may order this test:
Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. St Louis, MO: Elsevier; 2017:chap 30.
Review Date: 11/10/2016
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 9-1-1 for all medical emergencies. Links to other sites are provided for information only—they do not constitute endorsements of those other sites. © 1997-2010 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.