Specimen Requirements

1 paraffin block.
Note:  The performance and quality of immunohistochemical stains for formalin-fixed, paraffin-embedded tissue is critically dependent on proper fixation of tissue specimens. Immunohistochemical staining of steroid hormone receptors is especially sensitive to fixation conditions. For optimal results, tissue specimens with maximum dimensions of 1 x 1 x 0.4 cm must be fixed for a minimum of 6 hours and a maximum of 72 hours in fresh, neutral-buffered formalin. The formalin solution must be <1 month old.