With the help of blood differential test, immature cells or abnormal growth of cells can be detected. Diagnosis of conditions like inflammation, leukaemia, or an immunity disorder can also be done through this test. Blood constitutes of various types of leukocyte (white blood cells) like eosinophil, neutrophil, monocyte, lymphocyte, and basophil. Since each of these white blood cells has different functions, there are different kinds of test carried out under blood differential test that measure the percentage of each type of white blood cell in blood.
Total Leukocyte Count (TLC) test is done to determine the number of white blood cells in an individual’s body. Since leukocytes determine the body's ability to fight against diseases or infections, the number of leukocytes in the blood can give an insight into how the body is recovering from a particular disease. On the other hand, Differential Leukocyte Count or DLC test is done to determine the percentage of the different types of white blood cells in an individual’s blood.
Procedure
The following steps are carried out in a blood differential test:
- The doctor collects a sample of blood. With the help of a small needle, blood is drawn from the individual’s arm.
- The laboratory specialist then puts a drop of sample blood on a glass slide. Then, the specialist smears the blood to spread it across the glass slide. The smeared blood is then stained with a dye that makes it easier to differentiate between the different types of white blood cells.
- Different types of WBCs are then counted. While this can be done manually, most of the labs now use automated count technology to get accurate information.
- Automated count technology utilizes electrical, photo detection or laser methods in order to provide accurate number, size and shape of the blood cells.
Note: The measurement of various types of blood cells like basophil, eosinophil, and lymphocyte might not be accurate if an individual is on corticosteroid medications. Thus, it is better to let the doctor know if someone is taking these medications before the test.
We hope that with this information, you will be able to get a better knowledge of the steps involved in the procedure of blood differential test.
