| Subject | Contents |
| Definition | A test that looks for "marker" (characteristic) antigens on the surface of B-lymphocytes (a type of white blood cell); these antigens may be helpful in the diagnosis of leukemia or lymphoma. |
| Alternative Names | B lymphocyte surface markers |
| How the test is performed | A sample of white blood cells is obtained by venipuncture or, less commonly, bone marrow biopsy . The test may also be done on a lymph node biopsy when lymphoma is suspected. Adult or child: Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet 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 . Infant or young child: The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding. Laboratory technique: Immunophenotyping (determination of the specific cell type and characteristics) of white blood cells obtained by venipuncture or bone marrow biopsy is the lab technique used for this test. |
| How to prepare for the test | Adult: No special preparation is usually necessary. Infants and children: The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:infant test or procedure preparation (birth to 1 year) toddler test or procedure preparation (1 to 3 years) preschooler test or procedure preparation (3 to 6 years) schoolage test or procedure preparation (6 to 12 years) adolescent test or procedure preparation (12 to 18 years) |
| How the test will feel | 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. |
| Why the test is performed | This test may be performed when other tests (such as the blood smear ) indicate abnormal white blood cells, when leukemia or lymphoma is suspected, or to differentiate the type of leukemia or lymphoma. |
| Normal Values | negative for monoclonal immunoglobulins Note: ml = milliliters |
| What abnormal results mean | Abnormal cell surface antigen studies in the blood or bone marrow may indicate lymphocytic leukemia (ALL or CLL ). Diagnosis of ALL is confirmed by demonstration of cell surface markers that are characteristic of primitive lymphoid cells. Less than 5% of cases of ALL are B-cell type; with abnormal B-lymphocytes that produce a monoclonal (single type) immunoglobulin that is bound to the surface membrane. CLL is characterized by an accumulation of mature-appearing lymphocytes; more than 95% of cases involve B-lymphocytes. In most cases, these lymphocytes have typical marker antigens on the cell surface, that is, a monoclonal immunoglobulin can be demonstrated on the cell surface. Abnormal cell surface markers on a lymph node or bone marrow specimen may support a diagnosis of lymphoma, which is an accumulation of abnormal, monoclonal B cells. The type of lymphoma is usually determined both by looking at the tissue under the microscope and by the specific pattern of immunophenotype. |
| What the risks are | excessive bleedingfainting or feeling light-headed hematoma (blood accumulating under the skin) infection (a slight risk any time the skin is broken) multiple punctures to locate veins |
| Special considerations | This test is highly specialized and may not be available at all general laboratories. 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. |
| | |