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You are here : Home  Blood Zone T-lymphocyte count ( T cell counts )
T-lymphocyte count ( T cell counts )T-lymphocyte count ( T cell counts )This is a blood test that measures the number of T-lymphocytes (a type of white blood cell).A T-cell count of may be helpful in the diagnosis of immunodeficiency diseases and lymphocytic diseases. It is also used to monitor how well therapy for these types of diseases is working. Lymphocytes are white blood cells that are part of the immune system. T lymphocytes (T-cells) act directly (cellular immunity) to fight diseases or organisms, stimulate B lymphocytes (helper T-cells), or suppress some B lymphocyte functions (suppressor T-cells). About blood About Blood Transfusion Autologous Blood Transfusion Effects of blood transfusion Blood facts Blood Diseases and Disorders Eligibility test Why many people don't donate blood Blood Components About Lymphocytes Cells T-lymphocyte count ( T cell counts ) Test Human immune system Blood Donor Requirements Blood Products Blood Substitutes Blood types Apheresis Q&A - Blood Foods to increase your blood Food to increase immunity Rh Factor What are Blood Groups Health calendar Glossary
Normal Values
How the test is performed Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding. For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding. In the laboratory, the white blood cells are separated from the other blood cells. A stain or other substance that "labels" the cells is added to help identify which type of white blood cells are present. B and T lymphocytes look the same under an ordinary microscope. However, they may be differentiated with an electron microscope. B or T lymphocytes may also be counted using immunofluorescence ( Immunofluorescence is a laboratory technique to identify specific antibodies or antigens ) or by flow cytometry. T cells can also be differentiated by the E rosette test (Blood is mixed with sheep red blood cells. The T cells will cling to the sheep cells and produce a distinctive rosette pattern). Special considerations This test can be affected by
People with decreased T - lymphocytes may not react to diagnostic skin tests. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. See also Lymphocytes |
Related pages CD4(T-cell tests) More Blood Tests About Lymphocytes Blood Cells Complete Bloodcount Clinical Significance Tests and Normal Haematology Reference Values |
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