Total Leucocytes / WBC Count (TLC) Test

Leucocytes, also known as white blood cells (WBCs/leukocytes), are produced in the bone marrow and circulate in the blood and lymphatic system (a network of tissues, organs, and vessels). They include five main types: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Together, they play a crucial role in protecting the body against infections, inflammation, and other diseases.

The full form of TLC is total leucocyte count (TLC). It measures the total number of leucocytes present in the blood and is commonly used to assess overall immune function. Doctors usually use this test to help detect and monitor infections, immune-related conditions, and various haematological (blood-related) disorders.

You may need a TLC test if you have signs of infection, inflammation, or an autoimmune condition.

• Common symptoms of infection include:
• Fever
• Chills
• Persistent cough
• Body aches
• Headache
• A wound that does not heal or has pus
• The most common symptoms of inflammation or autoimmune diseases include redness, swelling, heat, and pain in the affected area. Symptoms may vary depending on the affected body part and the specific condition.

Individuals who should take this test include:

• People with conditions that weaken the immune system.
• Those taking medicines that suppress immune function.
• Newborns and children undergoing routine screening.
• Newborns or children with signs suggestive of a WBC disorder or infection.

The frequency of the TLC blood test depends on your health condition, symptoms, and the doctor’s advice.

A TLC test can help identify or monitor several health conditions that may cause abnormal leucocytes/WBC levels. These include:

• Infections: Such as bacterial or viral infections that trigger an immune response.
• Autoimmune and inflammatory diseases: Conditions where the immune system attacks healthy tissues.
• Allergic reactions: Which can increase certain types of leucocytes.
• Immune system disorders: Disorders such as HIV that can weaken the body’s defence system.
• Bone marrow disorders: Conditions that affect the production of leucocytes.
• Liver or spleen diseases: Liver or spleen conditions, such as hepatitis or spleen enlargement.
• Certain cancers: Such as leuka

What to Expect Before the TLC Test

No fasting is required for a standalone TLC test. You can eat and drink normally. However, if it is part of a broader package that includes fasting tests, your doctor may advise fasting for 8-12 hours. Avoid strenuous exercise for 24 hours before the test, as intense physical activity can temporarily raise TLC levels and affect interpretation. Always inform your doctor about any ongoing medications.

What to Expect During the Blood Collection

A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein; you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the TLC Test

A small cotton swab and bandage are placed over the site to stop any minor bleeding. You can return to normal activities immediately. Minor bruising is normal and disappears quickly. If dizzy, sit and rest for a few minutes.

The TLC test primarily measures:

• TLC/WBC count:The overall number of leucocytes/WBCs present in the blood.

The TLC test normal range is indicated in the table below.

Note:

• Normal TLC/WBC values may vary depending on age, overall health, and the laboratory method used.
• Test results should always be interpreted by a doctor along with clinical symptoms and medical history.

The table below provides a general interpretation of TLC test results based on whether levels are high or low:

Note:

• High TLC levels may also be associated with factors such as stress, smoking, pregnancy, or certain medications.
• Results should always be interpreted along with symptoms and other diagnostic test results.

The TLC test is a simple and commonly performed blood test. While it is generally safe, there are minimal risks and certain limitations to consider.

Risks:

These are rare and usually resolve quickly on their own.

• Mild pain or discomfort at the site of blood collection.
• Slight bruising or bleeding at the needle puncture site.

Limitations:

• The TLC test only measures the total number of WBCs and does not identify the exact cause of abnormal levels.
• Abnormal results may be influenced by factors such as stress, medications, pregnancy, or recent infections.
• It cannot differentiate between specific types of white blood cells without a differential leucocyte count (DLC).
• Further tests are often required for accurate diagnosis and confirmation of underlying conditions.

The TLC test is often performed along with or followed by other tests to better understand the cause of abnormal white blood cell levels. Common related and follow-up tests include:

• Complete blood count (CBC)
• Differential leucocyte count (DLC)
• Peripheral blood smear (PBS)
• Bone marrow tests

Pro Tip: For the most stress-free experience, book a TLC test on PharmEasy. Enjoy professional service and accurate results without stepping out of your house.