That’s interesting, is this outside of the US? I’ve never seen it indicated this way in a Pathology report or in a lab SOP, in or out of the US.

Not sure if OP was involved in conducting the study, but I’m curious why they decided to fix the tissue in 4% neutral buffered formalin and not 10% which is typically standard practice. Underfixation of tissue can lead to false negative staining in IHC, so sort of curious what the rationale was behind that decision.