A complete blood count, or CBC, is a panel of tests that will help identify anemia, infection and other blood disorders. The CBC will measure the value of red and white blood cells, hemoglobin and hematacrit, and platelets, but the CBC does not indicate if there has been damage to the heart muscle. It can identify abnormal values that would raise suspicion and lead to further investigation.
Red Blood Cells
Red blood cells are responsible for transporting oxygen from the lungs to the rest of the body. A component of red blood cells is hemoglobin. Low levels of hemoglobin can be caused by things such as anemia, bleeding or iron deficiencies. High levels of hemoglobin could indicate dehydration, low levels of blood oxygen or a congenital heart disease. Hematacrit is also a component of the red blood cell count. Hematacrit identifies the volume percentage of whole blood that is made up of red blood cells. High or low levels of hematacrit may reflect the same concerns noted with high or low hemoglobin values.
White Blood Cells and Platelets
White blood cells, also called leukocytes, help defend the body against infection. White blood cells are products of the immune system and help to indicate how the immune system is responding. Diseases that can lower the white blood cell count include liver and spleen disease or bone marrow infection. Elevated white blood cell counts can occur from infections, inflammation and tissue damage such as burns. Platelets, or thrombocytes, help the blood to clot. Abnormal platelet counts help to identify specific clotting disorders, cancers and types of anemia.
Healthy Heart Blood Test
Measuring cholesterol levels can help to predict the risk of heart disease. Cholesterol levels are not part of a CBC. Cholesterol levels monitor high density lipoproteins, or HDL; low density lipoproteins, or LDL; and triglycerides. High levels of HDL have a protective effect by lowering the risk of a heart attack. LDL is the plaque-building fat in the blood, so the lower the level, the lower the risk of heart attacks. Triglycerides are the most common type of fat in the bloodstream. Abnormally high levels put you at a greater risk of heart disease.
Heart Damage
When the heart muscle has been damaged, specific cardiac blood tests are done to help confirm damage to heart muscle. The cardiac specific tests, which are not included in a CBC, are Troponin, and creatine kinase-myocardial band, or CK-MB. According to "Sheehy's Emergency Nursing Principles and Practice," Tropoin levels can be measured as early as three hours after injury to the heart muscle, and CK-MB levels may take four to 12 hours to elevate after injury. These laboratory tests are specifically for identifying myocardial injury.
References
- "Sheehy's Emergency Nursing Principles and Practice"; Emergency Nursing Association; Mosby Elsevier; 2010
- Medline Plus: Hemoglobin
