The cell membrane differentiation antigen test, which uses specific monoclonal antibodies to detect the type of antigens on the surface of lymphocytes, is used to understand the body’s immune status. Cell membrane differentiation antigen testing generally detects lymphocytes, which produce differentiated antigens on the surface of the cell membrane after participating in the body’s immune response. Testing for these antigens can help in the diagnosis of certain immune disorders, hematologic disorders, and other diseases. For example, CD4 is the receptor for HIV, and when the CD4/CD8 ratio decreases, it suggests that AIDS may be present. In addition, differences in cell membrane differentiation antigen test results can help determine the pathologic type of hematologic tumors, such as CD20 positivity in non-Hodgkin’s lymphoma and CD79a positivity suggestive of diffuse large B-cell lymphoma. Cell membrane differentiation antigen test is very widely used in the clinic, which can well help the diagnosis and identification of diseases.