One way by which doctors determine the presence of infections in the body is through a Complete Blood Count, more commonly called a CBC. It is a very common type of test that is often included in a person’s annual physical examination. A CBC test checks the three types of cells that circulate in your blood: red blood cells or erythrocytes, white blood cells or leukocytes and platelets or thrombocytes. Values that are abnormally low or high may in most cases indicate the presence of an infection or other forms of illnesses.
A CBC blood test with Differential or CBCD blood test is a type of test that focuses on the white blood cells. It has five components.
- Neutrophil granulocytes – may indicate either a bacterial infection or an acute viral infection; more common WBC type in adults
- Lymphocytes – an indicator for viral infections like rubella, measles and chicken pox, lymphocytic leukemia or in some, HIV infections; more common WBC type in children under 8 years old
- Monocytes – can possibly indicate monocytic leukemia, Rocky Mountain spotted fever, malaria, tuberculosis, regional enteritis, chronic ulcerative colitis and some bacterial infections
- Eosinophil granulocytes – asthma, allergic reactions and parasitic infections are ruled out by testing this WBC component
- Basophil granulocytes – may point to conditions related to the bone marrow such as lymphoma or leukemia
Reading a CBCD result
- Neutrophils. These are the body’s main defenders versus infections and antigens. For adults, the normal range of neutrophils is between 48 – 73 percent. 60.5% is the optimal level. Levels beyond 73 may be a sign of an infection. Levels below 48 may indicate that the immune system is under threat. For children, the normal range is 30 – 60 percent with the optimal reading at 45%.
- Lymphocytes. This component of the white blood cells defends the body against viral infections. The normal range is between 18 – 48 percent. 33% is the ideal count. For children, 25 – 50% is normal; 37.5% is optimal. High levels point to an active viral infection.
- Monocytes. These are the largest cells found in the blood stream. Considered as the body’s second line of defense, the count determines the overall level of body resistance. 4.5% is optimal in a 0 – 9% range. Results beyond 9% may indicate tissue malfunction. Leukemia, carcinoma and lymphoma are three such illnesses where major tissue malfunction occurs.
- Eosinophils. Parasites and most other infections are targeted by eosinophils. 0 – 5% is considered as the normal adult range with 2.5% being the optimal reading. Counts higher than 5 percentile usually indicate allergic reactions. On the other hand, low levels are usually not an issue.
- Basophils. Low levels of basophils are considered typical, with the normal adult range being 0 – 2%. 1% is considered optimal. Beyond 2% may be cause for further evaluation. Basophil counts are used to identify the body’s resistance to allergies.
The white blood cells are the body’s bodyguards. They work tirelessly to defend against infection caused by foreign organisms. The CBCD test determines whether the white blood cells are successfully doing their job or are losing the war against viruses and bacteria. If you see unfavourable results in your CBCD test, don’t panic yet. For an accurate interpretation of your CBCD test, consult your physician. He will be able to tell you what exactly is going on in your body. Your doctor will provide you with the necessary treatment options or require more tests for further evaluation.