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- $Title{Complete Blood Count}
-
- A Medical Times Patient Education Chart
- (C) Romaine Pierson Publishers, Inc.
-
- ------------------------------------------------------------------------------
-
- What Can the Blood Tests Tell?
-
- The tests done as part of a complete blood count (CBC) are useful in
- diagnosing some illnesses. The major ones are anemia (which is a shortage of
- red blood cells or of hemoglobin, the blood protein that carries oxygen) and
- leukemia (which is a type of cancer that causes abnormal increases in white
- blood cells). CBCs can also help track progress in treating diseases.
- The blood sample is usually taken from a vein in the arm, but may be
- drawn from the foot, finger, or ear. Your doctor will use the blood test
- results along with the results of your physical exam to diagnose a disease or
- assess your health.
- Test results will vary even in healthy people because of personal
- differences such as age and sex. The normal ranges given here are for adults.
- Although the measurement terms may be unfamiliar, they are used here so you
- can compare them with your own test results.
-
- The Red Blood Cell Count
-
- The number of red blood cells (RBCs) within the normal range varies from
- 3.6 to 5.4 million per cubic millimeter. The average for females is 4.5
- million and for males 5 million. Too many RBCs might be a sign of lung
- disease or congestive heart failure, the inability of the heart to pump blood
- efficiently. Too few RBCs, a condition known as anemia, can be caused by
- bleeding, leukemia, kidney disease, hormone problems, and other chronic
- diseases. Radiation and drugs used to treat cancer and other conditions may
- damage the bone marrow, where RBCs are formed, and so prevent the formation of
- enough new RBCS.
-
- Hemoglobin: The Oxygen Carrier
-
- Hemoglobin is the red pigment in RBCs that binds with oxygen, so the
- amount of hemoglobin is a measure of how much oxygen the RBCs are capable of
- carrying to other cells. The normal levels range from 12 to 16 grams per
- deciliter for women and 13.5 to 18 for men. Low levels can result from
- inherited anemias, such as sickle cell anemia and thalassemia, or from anemias
- due to iron and vitamin deficiencies.
-
- The Hematocrit: Ratio of Red Blood Cells
-
- The hematocrit measures the percentage of blood volume made up of RBCs.
- The nominal ranges are 37% to 47% for women and 40% to 54% for men. Anemia,
- leukemia, blood loss, and kidney failure cause lower levels. Lung disease and
- loss of body fluids, such as that which occurs with severe burns, surgery, and
- shock, could result in higher percentages of RBCs.
-
- White Blood Cells: The Defense Team
-
- In normal adults, the total number of white blood cells ranges from 4,000
- to 10,000 per cubic millimeter. Higher levels could be caused by infection,
- leukemia, acute bleeding, stress, and conditions that cause damage to the
- cells, such as heart attacks. Radiation, viral illness, and a weakened immune
- system are some of the causes of a decreased number of WBCs.
- Each of the five different types of white blood cells performs a special
- job in defending the body against bacteria and other harmful matter. The
- percentage of each type of WBC in the blood is measured by the differential
- count or "diff." (See front of chart for WBC types and normal ranges.)
- Neutrophils and monocytes are the cells most active against bacterial
- infections. Lymphocytes help produce antibodies that can inactivate harmful
- substances entering the body, including infectious agents. Eosinophils and
- basophils are involved in allergies.
-
- The Red Blood Cell Indices
-
- Three measurements, known as the red cell indices, can help your doctor
- identify the specific types of anemia. Knowing the type of anemia and its
- possible cause makes it possible to treat the disease appropriately.
-