Neutrophils are a type of white blood cell. In fact, they are the most abundant type of white blood cells. They are a part of the body's immune system and are the first cells to increase in case of an infection, especially bacterial infection. They are the first line of defense of the body in case of an infection.
Neutrophil Blood Test
The neutrophil blood test forms part of the differential white blood cell count which also measures other white blood cells like lymphocytes, monocytes and basophils.
How the Test is Performed
A health care provider will take blood from your vein. This is collected in an airtight container. A laboratory specialist takes a drop of blood and smears it onto a glass slide. This smear is stained with a special dye which helps to differentiate between the various types of blood cells. A health care provider or a computer counts the total number of cells. This test shows if the different cells are in proper proportion to one another. This gives the proportion of neutrophils in the blood.
Why the Test is Performed
This test is used for the following:
1. To detect any acute infection, especially bacterial infection.
2. As a part of the estimation of total white blood cell count in other inflammatory conditions.
Neutrophils in the blood can be expressed either as absolute neutrophil count or as a percentage of the total white blood cell count. A normal absolute neutrophil count is 1500 cells per microliter. An absolute count of less than 500 cells per microliter is known as neutropenia and significantly increases the risk of infection. The most common condition where an absolute neutrophil count would be measured is in the setting of chemotherapy for cancer. Neutrophilia is an elevated count.
Neutrophils can also be expressed as a percentage of the total whole blood cell count. Neutrophils constitute 40-60% of the total white blood cells.
Abnormal Neutrophil Blood Test
An abnormal neutrophil blood test means either an increase or decrease in the proportion of neutrophils in the blood.
An increase in neutrophils can occur in the following conditions:
1. Acute infection
4. Rheumatoid arthritis
5. Rheumatic fever
6. Acute stress
9. Myelocytic leukemia
A decrease in the number of neutrophils can occur in the following conditions:
1. Aplastic anemia
4. Radiation therapy or exposure
Risks of the Test
The risks associated with the test are the risks associated with having your blood taken. These include:
1. Excessive bleeding
2. Fainting or feeling lightheaded
3. Hematoma (accumulation of blood under the skin)
4. Infection (a slight risk of infection is always there when the skin is abraded)
1. Laboratory test handbook by David S Jacobs, 1996.
2. Neutrophils methods and protocols: Volume 412 by Mark Thomas Quinn, Frank Deleo, Gary M Bokoch, 2007.