Much of the work of the White Blood Cells is helping the body fight infections. However, they have several enemies determined to lower their numbers and, therefore, their defensive power. They include steroids, chemotherapy and radiation therapy in cancer treatment, as well as bone marrow or stem cell transplant and surgery.
There are several types of WBCs with different functions in the fight against the body's invasion by microbial infections. However, neutrophils are the most important. Their suppression or reduction in number leads to a weakened immune system which in turn opens the gates for all kinds of infections to flood the body. Therefore, it is necessary to measure the number of neutrophils in the body, which is better known as Absolute Neutrophil Count (ANC).
Whenever your doctor wants to determine your level of immunity, he or she will most probably go for the ANC test. If found out to be low, then you may be considered to be neutropenic. The condition is known as neutropenia.
Keep in mind that ANC is part of the larger blood count; the Complete Blood Count (CBC). Nevertheless, you may still be neutropenic even when your CBC appears to be normal. Since neutrophils usually account for the largest number of white blood cells, their reduced number will be evident in low WBC count.
A Complete Blood Count (CBC) gives you the levels of the white blood cells, red blood cells and platelets. On the other hand, Absolute Neutrophil Count (ANC) will let you know the percentage of neutrophils in the white blood cells in your blood.
Here is a formula for the calculations:
[(% of neutrophils + % of bands) / 100] × WBC count = ANC
In a simple explanation, you should divide the total of neutrophils (add the percentage of segmented neutrophils to the percentage of bands) with 100 and multiply the result with the White Blood Cells count. Remember that segmented neutrophils are mature neutrophils while bands are immature ones. To give just but an example, assume the percentage of your neutrophils is 100 and that of bands is 10 while your WBC is 1,500, your calculations should look like this:
((70 + 5) / 100) x 1,500
(75 / 100) x 1,500
0.65 x 1,500 = 975
The measurement of ANC is normally taken when deciding on chemotherapy for cancer patients. Neutropenia comes in when your ANC falls below 1,000 for every microlitre. When it goes below 500 per microlitre, the condition is known as Severe Chronic Neutropenia and you are at serious risk of infection.
The common signs of infection in a person whose immune system is intact are fever, pain, swelling, redness and purse. These signs are usually a result of the fight between neutrophils and germs. When the ANC falls, these signs will no longer show simply because there are no signs. Consequently, it becomes a little harder to determine the presence or absence of an infection. Fortunately though, the monocyte (another WBC) can cause fever in a neutropenic person.
The measuring of ANC should not be a one-time affair especially in cancer patients whose body response to treatment should be monitored. In that case, neutropenia may indicate the need for a reduced chemotherapy dosage or even delaying the next treatment. In addition, doctors can predict the onset of signs related to neutropenia including fever after chemotherapy treatment thus helping determine the immunologic status of the patient.
In order to determine the need to include antibiotics to the treatment of cancer, ANC is important. In addition, it helps doctors decide on whether or not to keep in-patients in isolation in order to protect them from infections as well as advise out-patients to keep away from potential harmful environments such as crowded places. Therefore, ANC is one of the most effective ways of not only monitoring treatment progress but also preventing infections.