Test Name: FMC7
Methodology: Flow Cytometry
Staining for FMC7 highlights a subset of mature B-lymphocytes, which represent >50% of peripheral blood B-lymphocytes in adults. FMC7 antibodies actually highlight an epitope present on the extracellular domain of the CD20 molecule, which is detected variably at different stages of B-cell maturation due to sensitivity of the specific antibodies to the variable levels of membrane cholesterol characteristic for these stages of maturation. FMC7 is detected on many mature B-cell lymphomas/leukemias and is characteristically absent in CLL/SLL with classic immunophenotype, which also shows decreased expression of CD20.
Testing for this antigen is typically performed as a part of the B-cell neoplasm add-on panel. For customized testing panels including this antigen, please contact the Medical Director of the Flow Cytometry laboratory.
Storage and Transport
Maintain specimen at room temperature. Do not refrigerate or freeze. Use cold pack for transport, making sure cold pack is not in direct contact with specimen.
Specimen Rejection Criteria
Turn Around Time (TAT): 24 hours
CPT Codes*: 88184, 88185, 88187, 88188, 88189
*The CPT codes provided with our Test Descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.