DLC (Differential leukocyte count)

Your doctor may order this test to check for conditions such as anaemia, infections, autoimmune disorders and leukaemia. Symptoms that could relate to inappropriate levels of WBCs in the body are as follows:

• Weight loss
• Fatigue
• Bruising
• Fever
• Body aches
• Chills
• Headache

Usually, this test is ordered along with a complete blood count (CBC) test. CBC test may be done for a routine health check-up or if the doctor observes symptoms of infection.

A DLC test also helps in monitoring the ongoing treatment of some health conditions.

No special preparation is needed before a DLC. Tell your doctor about all the medications you are taking as some types of steroids can interfere with the results of this test. Make sure to inform your doctor about any past illnesses. Discuss your symptoms in detail and let your doctor know if you are concerned about the test procedure.

At the testing centre, a nurse or laboratory technician will collect a small amount of blood from a vein in your arm, using a sterile needle. You may feel a slight pain when the needle is inserted; however, it will go away soon. 

The sample will be transferred into a specialised container, and immediately sent to the laboratory for analysis. Some people may observe a small amount of bruising on their arm due to the procedure; this too fades away on its own. In case the bruising persists, consult your doctor.

On the basis of the laboratory where the test is performed, the sample can be evaluated for WBC levels either manually or using an automated machine. For automated testing, a diluted sample of the blood is added into the machine and analysed with cell/light scatter pattern. For every cell that passes through the machine a specific pattern is generated on a screen. The intensity and pattern of scattered light help evaluate the differential white blood cell count. The automated machine has higher precision than the manual method.

Normal results:

The results for the DLC are given in terms of percentages. The normal ranges for the different WBCs are as follows:

• Basophils: 0.5%-1%
• Eosinophils: 1%-4%
• Neutrophils: 40%-60%
• Band (young neutrophils): 0%-3%
• Monocytes: 2%-8%
• Lymphocytes: 20%-40%

Abnormal results:

Abnormal WBC values could be a sign of an underlying health condition. Sometimes, an increase in the levels of one type of WBC can lead to a decrease in the levels of another type. Usually, a rise in WBCs is due to an inflammatory condition, an immune response to infection or a tumour. The following table details the factors associated with the change in the levels of different WBCs:

Please consult the doctor to understand what the test results precisely mean for you as the levels of WBCs can vary from person to person depending on age, gender, and health conditions. WBC levels also vary during pregnancy.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.