CD45

Formalin-fixed, paraffin embedded tissue block or cell block, or 1 unstained charged slide for each test requested plus 3-4 additional unstained slides cut at 4 microns. Adequate space on each slide for control tissue is required.

CD45 is a family of 5 to 8 glycoproteins that are expressed on the cytoplasmic membrane of all cells of hematopoietic origin, except erythrocytes. It is highly specific, and its expression is indicative of lymphoid and/or myeloid origin. Some hematolymphoid neoplasms may show aberrant loss of CD45 expression, and so, its absence does not rule out the possibility of tumors of hematolymphoid origin.