CD4 is a cell surface-associated protein expressed at relatively high levels in helper T cells, and at lower levels in monocytes. CD4 is also the receptor for HIV. CD4 is aberrantly decreased in a subset of T cell neoplasms, and is commonly expressed in monocytic/histiocytic neoplasms.
Subcellular Localization: Membranous
Disease State: Anaplastic Large Cell Lymphoma (Systemic or Cutaneous), Angioimmunoblastic T Cell Lymphoma, Blastic Plasmacytoid Dendritic Cell Neoplasm, Peripheral T Cell Lymphoma, NOS (of Large Cell Type)
CPT Code(s): 88342 or 88341 (reference only; CPTs may vary)
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