PAS x40 - RCPA

Tissue for light microscopy:• describe the macroscopic appearances of the biopsy• select at least 5mm of cortex, preferably more• place it in formalin and fix• mercuric fixatives e.g. Dubos-Brazil have also beenused because deposits and nuclear detail are betterseen, but they are toxic and for Occupational Health& Safety reasons we no longer use them• process to paraffin and cut sections– 0.5μ thick for H&E and special stains– 2μ thick for Congo red and immunostains