The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. 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 . Therefore, the risk for infection may be somewhat greater than when venipuncture is performed on a person with a normal immune system. It is also used to monitor the response to therapy for these type of diseases.
Lymphocytes are white blood cells that are part of the immune system.
A flow cytometric measurement is more accurate than manual counts. 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.