Total Leucocytes / WBC Count (TLC) Test

The Total Leucocyte (WBC) Count is a test that measures the amount of white blood cells present in the body. This test is part of the complete blood count (CBC). It is generally used to detect different infections or conditions that may affect general health.

White blood cells (leukocytes) play an essential role in the body's immune system. These cells fight infection by attacking alien or foreign bacteria, viruses and germs that invade the body.

An increase or decrease in the number of WBCs can help diagnose many medical conditions, such as infections, autoimmune diseases, immune deficiencies and blood disorders, etc. The Total Leucocyte (WBC) Count also helps doctors monitor the progress of the patient undergoing chemotherapy, radiation treatment and other therapies given to cancer patients.

There can be a substantial range variation in the Total Leucocyte (WBC) Count in the following groups of people:

• Pregnant women
• Newborns
• Children smaller than 2 years of age

Other Names of Total Leucocytes (WBC) Count Test?

• Total leucocyte count
• white blood cell count
• Total and differential leucocyte count
• Total white blood cell count
• TLC test

What does the test detect/measure, and why is this prescribed?

The Total Leukocyte Test measures the total amount of all the different types of white blood cells present in the blood. The doctor may advise this test if someone exhibits symptoms of any infection/disease/disorder. It may be prescribed as a routine test.

The symptoms of a low leukocyte can be:

• Body pain
• Fever with chills
• Unexplained headaches
• Frequent sickness

High leukocyte levels don't usually cause symptoms, but the underlying conditions causing the high levels may generate their own set of symptoms.

The Total Leucocyte (WBC) Count Test requires a blood sample.

Test preparation

The Total Leucocyte Test preparation does not include fasting. It is important to inform the doctor about all medicines, supplements and therapies the patient may be undertaking to avoid inaccuracy in results.

Test inclusions: What parameters are included?

The Total Leucocyte (WBC) Count includes a single parameter:

• Level of white blood cells in the blood

Infections, Autoimmune disorders, Hereditary disorders, Leukaemia and several other medical conditions

A normal white blood cell count usually indicates that all is well with the immune system and it is functioning as normal. The normal range for WBC levels is between 4,000 and 11,000cells/mm³

These ranges may differ slightly for pregnant women, infants and children below 2 years.

The normal values and reference range of tests may vary from lab to lab. Please consult a doctor to understand the interpretation of your lab reports.

Total Leucocyte (WBC) Count Test results are not considered normal when they are either higher or lower than the normal range as per the patient’s age.

A low/high leukocyte count can indicate a blood disorder or any other medical condition. To identify the exact cause of a high or low Leukocyte count, the physician will take several factors into consideration:

• Current medications
• Symptoms
• Medical history.

Low white blood cell count

Leukopenia is the term used to denote a low WBC count. This can be caused by:

• HIV infection/AIDS
• Autoimmune diseases(e.g., lupus)
• Bone marrow trauma/diseases
• Lymphatic cancer
• Severe infections like malaria
• Enlarged spleen
• Liver disorders
• Radiation therapy for cancer treatment
• Medications such as chemotherapy and antibiotics
• Alcoholism

High white blood cell count

Leukocytosis is the term used to denote a high WBC count. It can be caused by:

• Bacterial Infections such as tuberculosis, sepsis or septic shock
• Fever
• Injuries or burns
• Pregnancy
• Seasonal allergies
• Asthma
• Recent vaccination
• Medications like corticosteroids, epinephrine and non-steroidal anti-inflammatory (NSAID) drugs
• Stress
• Tissue trauma/damage
• Acute hemolysis
• Haemorrhage or bleeding
• Heart attack
• Surgery

An increased white blood cell level may be chronic in cases of

• Smokers
• Bone marrow tumour
• Cancers like Leukaemia, Myeloproliferative neoplasm
• Inflammatory conditions like arthritis and bowel disease
• Obesity
• Inflammation of the blood vessels

WBC count tests serve as an indicator of conditions affecting the body. The doctor may prescribe additional tests to diagnose the exact cause of abnormal white blood cell count and necessary direct treatment.