CD19, like the CD79 complex and cytoplasmic CD22, is a pan-B-lineage antigen that is first expressed in very early B-lymphoid progenitors, and continues to be expressed at variable levels through terminal B-lymphoid differentiation in plasma cells. With the exception of true plasma cell neoplasms and classical Hodgkin lymphoma, the great majority of mature and immature B-lymphoid neoplasms express CD19. Some neoplasms such as hairy cell leukemia overexpress CD19, while others such as follicular lymphoma typically underexpress CD19. Rare non-B-lymphoid neoplasms express CD19, most notably acute myeloid leukemia (AML) bearing the t(8;21).
Subcellular Localization: Mainly membranous; partially cytoplasmic
Disease State: B Cell NHL with Plasmacytoid Differentiation, B Cell Non-Hodgkin Lymphoma (not otherwise classified), Burkitt's Lymphoma, Chronic Lymphocytic Leukemia / Small Lymphocytic Lymphoma (CLL/SLL), Diffuse Large B Cell Lymphoma, Follicular Lymphoma, Hairy Cell Leukemia, HIV-Associated Lymphoma, Lymphoplasmacytic Lymphoma, Mantle Cell Lymphoma, Marginal Zone/MALT Lymphoma, Nodular Lymphocyte-Predominant Hodgkin Lymphoma, Plasma Cell Myeloma/Neoplasm, Precursor B-Lymphoblastic Lymphoma/Leukemia (B-ALL)
CPT Code(s): 88342 or 88341
Turnaround Time: Within 1-2 business days of receipt
Schedule: Monday - Friday
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR -
• 1 unstained slide for each test requested plus 3-4 additional unstained slides cut at 4µm