Total Leucocytes Count (TLC)

This test is done to check for the following conditions:

• Hidden infections 
• Blood disorders 
• Autoimmune disorders (where the immune system destroys normal body tissue)
• Immune deficiencies
• Allergic reactions
• Inflammation 
• Blood cancers, like lymphoma or leukaemia

The test also helps the doctor to monitor the effectiveness of cancer treatment.

Your doctor may recommend this test if you have symptoms of a low WBC count, such as:

• Fever
• Headache
• Body ache
• Chills

Increased WBC count does not usually cause symptoms, but the conditions responsible for it would. 

After starting treatment for the cause of increased or decreased WBC count, your doctor may order this test periodically to check the progress of the condition and adjust the treatment accordingly.

Your doctor may also routinely perform a TLC with a complete blood count during your annual physical examination.

You don’t need any special preparation before this test. If you are on any medications, inform your doctor as some drugs can affect the test results. Drugs that can decrease your WBC count are:

• Antithyroid drugs
• Anticonvulsants
• Antibiotics
• Arsenicals
• Chemotherapy drugs
• Captopril
• Chlorpromazine
• Clozapine
• Histamine-2 blockers
• Water pills (diuretics)
• Sulphonamides
• Terbinafine
• Quinidine 
• Ticlopidine 

Drugs that can increase your WBC count are: 

• Corticosteroids
• Beta-adrenergic agonists (e.g., albuterol) 
• Epinephrine
• Heparin
• Lithium
• Granulocyte colony-stimulating factor

Stress and physical activity may also increase WBC count. In the final month of pregnancy and during labour, the WBC count may be raised. People who have undergone a splenectomy will have a persistent, mildly elevated WBC count.

TLC is performed on a blood sample. A laboratory technician will withdraw a small amount of blood from a vein in your arm. You may experience some pain when the needle goes in, but this will fade quickly. 

Some minor risks associated with blood tests are:

• Feeling lightheaded
• Excessive bleeding
• Bleeding under the skin
• Infection at the needle insertion site
• Multiple punctures to locate the vein

Normal results:

The normal WBC count changes according to age. Normal count for different age groups is as follows:

• Adult: 4500-10500/mm3
• Child (12-18 years): 4500- 13000/mm3
• Child (6-12 years): 4500-14500/mm3
• Child (1-6 years): 5000-17000/mm3
• Child (below 1 year): 6000-17500 
• Till 4 weeks: 6000-18000
• Till 2 weeks: 6000-21000
• Newborn: 10000-26000/mm3

Tests results vary slightly from laboratory to laboratory. Please speak to your doctor to know what exactly your results mean for you.

Abnormal results: 

WBC count less than 3700/mm3 in adults is called leucopenia. Leucopenia may be seen in the following conditions:

• Bone marrow depression due to heavy metal toxicity, radiation or medications
• Viral infections and overwhelming bacterial infections
• Bone marrow disorders such as:
  • Aleukaemic leukaemia (a rare type of cancer in which the WBC count is normal or below normal)
  • Aplastic anaemia (a condition in which the bone marrow cannot produce sufficient blood cells)
  • Pernicious anaemia (a condition caused by vitamin B12 deficiency)
  • Myelodysplastic syndrome (a condition where blood-forming cells in the bone marrow become defective)
• Dietary deficiency
• Autoimmune disorders
• Spleen and liver diseases
• Marrow-occupying diseases such as fungal infection or metastatic tumour

WBC count greater than 11000/mm3 in non-pregnant adults is called leucocytosis. The following conditions can cause leucocytosis:

• Infections
• Leukaemia
• Trauma or tissue injury
• Allergies
• Stress
• Bone marrow tumours
• Asthma
• Pregnancy
• Inflammation or inflammatory conditions, such as bowel disease or arthritis

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.