The most common type of blood test performed is the complete blood cell count, often referred to as the CBC. The CBC is a series of tests of the blood that provides the health-care provider with a large amount of information about many of the systems in the body.
These tests are inexpensive, easy, rapidly performed and fairly painless to the patient. All these factors make them one of the first tests that a health-care provider will perform when evaluating a patient.
This test counts the number of circulating red blood cells in 1 cubic millimeter of venous blood. Normal red blood cell values vary according to gender and age. Women tend to have lower values than men, and red blood cell counts tend to decrease with age.
When the value is decreased by more than 10 percent of the expected normal value the patient is said to be anemic. Low red-blood-cell counts can be caused by many factors, including hemorrhage, dietary deficiency of iron or vitamin B12, certain drugs, chronic illness and organ failure.
High levels can be an indicator of pathologies such as congestive heart failure or chronic obstructive pulmonary disease. These conditions cause the body to have a greater oxygen-carrying requirement. The body is therefore forced to produce more red blood cells in order to increase hemoglobin levels.
A normal adult male count will be between 4.7 to 6.1 units whereas an adult female will have a level closer to 4.2 to 5.4 units.
The major function of the white blood cell is to fight infection and react against foreign bodies. Therefore, an abnormal total white-blood-cell count occurs in cases of chronic infections, dietary deficiencies and autoimmune diseases.
A normal count in adults and children over 2 years old is between 5000 and 10000 cubic millimeters. Infants and children under 2 have higher levels.
Hemoglobin acts as the body's vehicle for oxygen and carbon dioxide transport. The concentration of hemoglobin in the blood determines its oxygen-carrying ability. Hemoglobin is also an important part of the body's acid-base buffer system.
Hemoglobin values decrease as we age. A typical adult male will have a level of 14 to 18g/dL while a typical adult female will have a slightly lower level at 12 to16g/dL. Both low and high hemoglobin levels put a strain on the heart and put patients at risk for conditions such as congestive heart failure and stroke.
The hematocrit is a measure of the percentage of total blood volume that is made up by red blood cells. Normal values vary according to gender and age. Overall, women tend to have lower values than men and values tend to decrease with age.
A normal level for an adult male is between 42 and 52 percent. A normal level for an adult female is between 37 and 47 percent.
Mean Corpuscular Volume
The mean corpuscular volume, or MCV, provides information about the size of the red blood cells. When the MCV is increased, the red blood cell is abnormally large. This is frequently seen in anemia caused by vitamin B12 or folic-acid deficiency. When the MCV is decreased, the red blood cell is abnormally small. This condition is associated with iron-deficiency anemia.
The average MCV is between 80 and 95 cubic millimeters.