B and T cell screen

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A test that makes a quantitative measurement of T and B lymphocytes in the blood.

Direct immunofluorescence; E-rosetting; T and B lymphocyte assays; B and T lymphocyte assays

Blood is drawn from a vein, usually from 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 cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in air-tight vials 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.

Blood could also be obtained by capillary sample (fingerstick, or heelstick in infants).

After the blood is drawn it goes through a two step process. First, the lymphocytes are separated from other blood elements. Once the cells are separated, identifiers are added to distinguish between T and B lymphocytes. The E-rosetting test identifies T cells and direct immunofluorescence is used to identify B cells.

No alteration in diet is necessary for this test.

Inform your health care provider of anything in your life that might affect your T and B cell count, including:

• X-rays
• Chemotherapy
• Surgery
• Steroid therapy
• Stress

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is performed to aid your health care provider in the diagnosis of immunodeficiency diseases. It may also be used to distinguish between benign and malignant lymphocytic disease. Finally, this test may be performed to monitor your response to therapy.

Review Date: 10/27/2005
Reviewed By: Frank A. Greco, M.D., Ph.D., Director, Biophysical Laboratory, The LaheyClinic, Burlington, MA. Review provided by VeriMed Healthcare Network.