Total Leucocyte Count

What is TLC?
Total Leukocyte Count (TLC) test measures the total number of all the leukocytes in the blood. Leukocytes are white-colored blood cells that defend our bodies against infections and diseases. This test helps determine the body’s capacity to fight diseases.

It is performed to diagnose infections and inflammation, monitor chemotherapy treatment, and diagnose bone marrow disorders.

A decrease in the TLC count is referred to as leukopenia, and it will decline the body’s ability to fight infections. An increase in TLC, known as leukocytosis, indicates acute infections and inflammation. It is followed up with other tests to determine the exact cause of the abnormal results.

 

Why is TLC done?
The Total Leukocyte Count Test is performed:

• As a part of Complete Blood Count (CBC) Test in regular health checkups
• To help diagnose infections and inflammation
• To help diagnose conditions that decrease WBC count like bone marrow disorders
• To monitor bone marrow function
• To monitor chemotherapy treatment

What does TLC Measure?
Blood is made up of different types of cells suspended in a fluid called plasma. These include erythrocytes or red blood cells, leukocytes or white blood cells, and platelets. Blood cells are produced by the hematopoietic cells in bone marrow and are then released into circulation. RBCs carry oxygen to the tissues, platelets help in blood clotting at a site of injury, and leukocytes form a part of the immune system of the body. WBCs are of five primary types: neutrophils, basophils, eosinophils, monocytes, and lymphocytes. Lymphocytes are further of three types: B-Lymphocytes, T-Lymphocytes, and natural killer (NK) cells. Neutrophils, basophils, eosinophils are collectively called granulocytes since they contain granules in cytoplasm.

Depending on various factors like age, gender, health condition, environmental factors, etc., varying amounts of different types of WBCs circulate in the blood. The bone marrow increases the production of WBCs in response to an infection or inflammation anywhere in the body. These WBCs are called to the site by a series of chemical signals, where they work to treat the condition. During this time, the total leukocyte count remains high in blood. Once the infection or inflammation subsides, WBC production by bone marrow decreases and WBC count in circulation falls back to normal levels. A continuously elevated WBC count may thus be an indication of a chronic condition that is not resolving naturally and might need urgent attention.

Apart from an infection or inflammation, WBC count in blood can also be affected by other conditions like disorders of the immune system, autoimmune conditions, cancer, etc. WBC count may be higher or lower than normal in these cases.

WBC count test serves as an indication of a condition affecting the body. Further tests are performed to confirm a particular condition and direct treatment.