A SIMPLIFIED MULTITISSUE CONTROL BLOCK

A modification of the multitissue control for immunohistochemistry is described. The multitissue core block (MTCB) was made by extracting ro ds of paraffin embedded tissue from existing blocks and inserting them according to a predefined pattern into a blank paraffin block. The ro ds were sealed into place with heat. The procedure is simple and requi res no complex equipment. The result is a structured multitissue contr ol that can be prepared facilely and quickly. Archived blocks can be u sed as a source of control tissue without destructive sampling. This c oncept was successfully tested with an automated immunohistochemical s taining system.