A blood sample is subjected to assays for CD3, CD4, and CD8 to determine the concentration of each molecule in the blood. The test is carried out before, during, and after the T cell lymphoma treatment in order to confirm its diagnosis. Lymphocytes, a particular kind of WBC, are what cause lymphoma. T cells or B cells can be lymphocytes. Helper T cells (CD4) or suppressor T cells can be found in the mature T cell (CD3) population (CD8). Therefore, in the lymphocyte test, the sum of the CD4 and CD8 cells should equal the CD3 value. You can determine the CD3 absolute count in this manner. An individual with a Human Immunodeficiency Virus (HIV) infection is given the test to assess their immune system.