The Differential Leukocyte Count (DLC) test is a key diagnostic tool used to evaluate the immune system by analysing the different types of white blood cells (leukocytes) present in the blood. Each type of leukocyte, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, plays a distinct role in defending the body against infections and other diseases. By measuring the relative percentage of these cells, the DLC test helps doctors identify various conditions such as infections, inflammations, allergic reactions, and blood disorders. In this article, we’ll explore the DLC test procedure, understand its normal range, and learn how to interpret the results for clinical insight. Let’s dive in. 

What is a Differential Leukocyte Count (DLC) Test and Why is it Done?

The Differential Leukocyte Count (DLC) test is a specialised blood test that measures the percentage of different types of white blood cells (leukocytes) present in the bloodstream. Unlike the Total Leukocyte Count (TLC), which provides the total number of WBCs, the DLC breaks this down into five main types: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Each type of white blood cell serves a specific function in the body’s defence system. Monitoring their individual levels helps doctors understand how the immune system is responding to infections, inflammation, allergic reactions, autoimmune conditions, or blood-related disorders. This test is commonly prescribed for the following purposes:

• To detect bacterial or viral infections
• To monitor chronic inflammatory or autoimmune diseases such as lupus or rheumatoid arthritis
• To evaluate allergic conditions or parasitic infections
• To help identify haematological abnormalities, including leukaemia
• To assess the immune response in people undergoing chemotherapy or taking immunosuppressive drugs

Types of White Blood Cells Measured in a DLC Test

The DLC test analyses five major types of white blood cells, each with a distinct role in protecting the body. Changes in their relative proportions can offer crucial insights into underlying health issues.

Neutrophils

These are the most abundant type of WBCs and act as the first line of defence against bacterial infections. A high neutrophil count often suggests a bacterial infection or acute inflammation, while a low count may indicate bone marrow suppression or a viral illness.

Lymphocytes

Lymphocytes are central to the body’s immune response. They help in fighting viral infections and producing antibodies. Elevated levels may point to viral infections or certain cancers, while reduced levels can occur in immunodeficiency states.

Monocytes

Monocytes help clear dead or damaged cells and fight off chronic infections. An increase may indicate tuberculosis, chronic inflammation, or autoimmune conditions.

Eosinophils

These cells play a key role in allergic reactions and combat parasitic infections. High eosinophil levels are commonly seen in conditions such as asthma, hay fever, or parasitic infestations.

Basophils

The least common WBCs, basophils, are involved in inflammatory responses and release histamine during allergic reactions. Elevated basophil counts can be linked to chronic allergies, certain blood cancers, or hypothyroidism.

DLC Test Procedure: What to Expect

The Differential Leukocyte Count (DLC) test is a straightforward blood test that can be done quickly and safely, even at home. Here’s how it works:

Sample Collection

A trained phlebotomist collects a small blood sample from a vein in the arm using a sterile syringe or vacutainer. For children or infants, a heel or finger prick may be used.

Sample Preparation and Staining

Once collected, the blood sample is placed on a glass slide and stained using special dyes such as Leishman stain. This process helps differentiate the various types of white blood cells under a microscope.

Manual vs Automated Testing

• Manual DLC: A laboratory technician examines the stained blood smear under a microscope and manually counts 100 white blood cells to determine their relative proportions.
• Automated DLC: Some labs use automated haematology analysers for quicker and more standardised results.

Duration and Pre-Test Instructions

The test itself takes only a few minutes, and results are typically available within 24 hours. Fasting is generally not required unless specified alongside other tests. However, it’s advisable to inform the healthcare provider about any ongoing medications, recent infections, or health conditions.

Difference Between DLC and Absolute Leukocyte Count (ALC)

While both DLC and ALC provide insights into white blood cells, they differ in how the information is presented and used:

• Differential Leukocyte Count (DLC) gives the percentage of each type of white blood cell (e.g., 60% neutrophils, 30% lymphocytes). It helps assess the balance and proportion among different WBC types.
• Absolute Leukocyte Count (ALC) calculates the exact number of each WBC type per microlitre of blood. It’s derived by multiplying the total WBC count (from the TLC) by the percentage obtained from the DLC.
  
  

Example:

If the total WBC count is 10,000 cells/L and neutrophils are 60%, the absolute neutrophil count would be 6,000 cells/L.

ALC offers more precise data in certain conditions such as neutropenia (low neutrophil count), and is particularly useful in chemotherapy monitoring, where exact cell counts are critical.

DLC Test Normal Range and Result Interpretation

The Differential Leukocyte Count (DLC) test provides percentage values for each type of white blood cell. These values are compared against established normal ranges to identify any abnormalities that might suggest infection, inflammation, or immune-related issues.

Normal Range of White Blood Cells (Percentage of Total WBC Count):

• Neutrophils: 40% – 75%
• Lymphocytes: 20% – 40%
• Monocytes: 2% – 10%
• Eosinophils: 1% – 6%
• Basophils: <1%

What Abnormal Values May Indicate:

• High Neutrophils: Suggests bacterial infection, physical stress, inflammation, or corticosteroid use.
• Low Neutrophils: May occur in viral infections, bone marrow suppression, or after chemotherapy.
• Elevated Lymphocytes: Common in viral infections, certain types of leukaemia, and tuberculosis.
• Low Lymphocytes: Could be due to autoimmune diseases, HIV, or prolonged illness.
• Increased Eosinophils: Often linked to allergies, asthma, or parasitic infections.
• High Monocytes: Seen in chronic infections like tuberculosis or autoimmune conditions.
• Elevated Basophils: May be associated with chronic allergies, hypothyroidism, or some blood cancers.

Other Blood Tests Often Done Alongside DLC

The Differential Leukocyte Count (DLC) is usually ordered as part of a broader blood analysis to provide a comprehensive view of a person’s health. Commonly associated tests include:

• Complete Blood Count (CBC): A CBC is a comprehensive blood test that examines red cells, white cells, and platelets to help identify issues such as anaemia, infections, and blood clotting abnormalities.
• Total Leukocyte Count (TLC): TLC measures the total number of white blood cells in the blood. It complements the DLC by providing the overall WBC quantity, which is necessary for calculating absolute counts.
• Erythrocyte Sedimentation Rate (ESR): The ESR test checks how rapidly red blood cells fall to the bottom of a test tube over a set period. An increased rate can be a sign of inflammation or an ongoing infection in the body.
• Haemoglobin and Haematocrit Levels: These values assess the oxygen-carrying capacity of the blood. Low levels may suggest anaemia, while elevated levels may occur in dehydration or lung diseases.
• Platelet Count: Platelets help with blood clotting. Abnormal counts can indicate bleeding disorders, bone marrow issues, or infections.

Note: Together with the DLC, these tests provide a more accurate picture of the immune system, blood function, and potential underlying illnesses.

Why Choose MaxAtHome for the DLC Test?

Getting a blood test doesn’t have to mean a trip to the lab. MaxAtHome brings professional diagnostic services right to your doorstep, making the process convenient, safe, and reliable.

Here’s why MaxAtHome is trusted for the DLC test:

• Home Sample Collection: Certified phlebotomists collect your blood sample from the comfort of your home, saving time and effort.
• Accurate, Expert-Verified Reports: Each test is processed in NABL-accredited labs and reviewed by experienced professionals for clinical reliability.
• Digital Report Access: Test results are delivered online, so you can view or download them anytime, anywhere.
• Trusted Service with Transparent Pricing: No hidden charges, and customer support is always available to guide you through bookings and results.

Cost and Availability

Understanding the cost and factors that influence it can help in making an informed choice. Here's what to know about pricing for the DLC test:

Factors Affecting the Price of Home Testing

The cost of the test may vary based on:

• The city or region where the test is booked
• Whether the test is ordered individually or as part of a health package
• Applicable home collection service charges
• Any ongoing offers or diagnostic packages

Despite these factors, MaxAtHome ensures that the pricing remains affordable and transparent, with no hidden fees.

Test Cost at MaxAtHome

MaxAtHome offers the DLC test at a competitive rate, with options for standalone testing or bundled in full blood panels. Pricing may vary slightly by location, but all bookings include home sample collection and digital reports at no extra cost.

How to Book the DLC Test at Home

Booking a Differential Leukocyte Count (DLC) test with MaxAtHome is quick, easy, and entirely online. Whether for routine monitoring or medical investigation, the process is designed for maximum convenience.

Here’s how to get started:

• Schedule the test online through our easy-to-use booking platform.
• Choose your preferred date and time for home sample collection.
• A trained phlebotomist will visit your home at the scheduled time to collect the blood sample safely.
• Access your test reports digitally, typically within 24-48 hours, reviewed by expert pathologists.

Whether you're monitoring an existing condition or investigating new symptoms, a Differential Leukocyte Count (DLC) test offers essential insights into immune health. With MaxAtHome, you can get tested without stepping out—benefiting from expert sample collection, reliable results, and complete convenience. Book your DLC test today by calling 01244781023 or schedule online through our easy-to-use booking platform.

Frequently Asked Questions

Q: What is the full form of DLC in a blood test?

DLC stands for Differential Leukocyte Count.

Q: How is a DLC test different from a CBC test?

While a CBC gives an overall picture of blood health, the DLC focuses specifically on the percentage distribution of different types of white blood cells.

Q: What is the normal range for neutrophils and lymphocytes in a DLC?

Neutrophils: 40%–75%, Lymphocytes: 20%–40%.

Q: Is fasting required for a DLC test?

No, fasting is generally not required unless combined with other tests that need it.

Q: Can a DLC test detect cancer?

While it cannot diagnose cancer directly, abnormal results may indicate conditions such as leukaemia, prompting further investigation.

Q: What does a high lymphocyte count indicate?

It may suggest a viral infection, chronic inflammation, or certain types of blood cancer.

Q: Why is eosinophil count important?

Elevated eosinophils may signal allergies, asthma, or parasitic infections.

Q: How accurate is a manual DLC test?

Manual DLCs are reliable when performed by skilled technicians, though automation adds consistency and speed.

Q: What are the risks associated with a DLC blood test?

It’s a low-risk procedure involving minor discomfort or bruising at the needle site.

Q: How long does it take to get DLC test results?

Results are usually available within 24 to 48 hours.

Q: Can stress affect DLC results?

Yes, physical or emotional stress may cause temporary changes in white blood cell counts.

Q: What infections cause a high neutrophil count?

Bacterial infections such as pneumonia, sepsis, or urinary tract infections can increase neutrophil levels.

Q: What is leukocytosis and how is it related to DLC?

Leukocytosis refers to a high total white blood cell count. A DLC helps determine which type of WBC is elevated.

Q: Should I be worried if my WBC differential is abnormal?

Not necessarily. Abnormal results should be interpreted by a doctor based on symptoms and other test findings.

Q: Is a DLC test done during routine health check-ups?

Yes, it’s often included in routine blood panels to assess immune system health.

Q: Can medications affect DLC test results?

Yes, certain medicines like steroids, antibiotics, or chemotherapy drugs can alter white blood cell levels.