The effects of tissue processing variables other than fixation on histochemical staining and immunohistochemical detection of antigens

In addition to the time, temperature, and type of fixation, multiple other factors may affect histological or immunohistochemical staining. Such varia bles include the interval between cellular death and fixation, the method o f tissue processing, preparation of paraffin blocks, the method of attachin g tissue sections to microscope slides, the interval between cutting tissue sections and immunostaining, the use of hydrophobic pens to demarcate tiss ue, and, most importantly, the staining methods themselves. The article rev iews contributions of the above factors as variables in histochemical and i mmunohistochemical staining. Problems in any of the above areas may be mist aken for problems with fixation, and it is important to determine rapidly t he actual sources of such problems.