CD3 Count

A CD3 test gives a quantitative value of total T cells in the blood and helps in evaluating the severity and prognosis of diseases that are associated with an abnormal T cell count. It also aids in monitoring the effect of treatment of various diseases associated with a high T-cell count. CD3 test or the test for T surface markers is mainly done in the following conditions:

• Leukaemia
• Lymphoma
• HIV infection
• After an organ transplant to monitor rejection

You don’t need to fast before a CD3 test. However, make sure to inform your doctor if you are on steroids, consume nicotine, involve in heavy exercise or have a viral infection as these conditions decrease the total T cells count.

A small amount of blood will be drawn from your arm and collected in a yellow top tube, which contains a special chemical called ethylenediaminetetraacetic acid. This test is performed using the flow cytometry technique and the entire test takes two days.

A flow cytometry technique uses specialised lasers to count and detect various characteristics of cells. In this technique, body cells are stained with a fluorescent dye and made to flow in a thin film while a laser is passed through it. Results are then evaluated on the basis of the intensity of fluorescence generated by the scattering of light.

Normal results:

• Total T cells (CD3+): 53% to 88%
• Helper T cells (CD3+, CD4+): 32% to 62%
• Suppressor T cells (CD3+, CD8+): 18% to 24%

The absolute counts are as follows:

• Total lymphocytes: 660-4600 /mm³
• Total T cells (CD3+): 812-2318 /mm³
• Helper T cells (CD3+, CD4+): 589-1505 /mm³
• Suppressor T cells (CD3+, CD8+): 325-997 /mm³

Abnormal results:

The values of T cells or CD3+ are found to be decreased in the following conditions:

• Immunodeficiency diseases present at birth such as DiGeorge syndrome and thymic hypoplasia or under-developed thymus gland. Characteristics of DiGeorge syndrome include deficiency of T cells, distinctive facial expressions, heart disease and decreased calcium in blood.
• In case of organ transplant (kidneys and heart), when the drug called OXT-3 is administered to prevent rejection
• Diseases that are treated with immune system-modifying drugs

The values of T cells or CD3+ appear to be increased in the following conditions:

• Suppressor T cells (CD3+, CD8+) are increased in infections caused by the following:
  • Epstein–Barr virus (infectious mononucleosis or kissing disease, which presents with a sore throat, fever and enlarged or swollen lymph glands)
  • Cytomegalovirus (herpes and infectious mononucleosis)
  • Hepatitis B virus (hepatitis B)
• T helper cells (CD3+, CD4+) are increased in diseases such as sarcoidosis, granuloma annulare, leukaemia and so on

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.