The purpose of my previous article was to identify many of the potential sources of error to be considered when evaluating quantitative data from immunohistochemistry (IHC) and histochemical reactions on sections.

Factors that may affect the evaluation of quantitative IHC data were listed but not necessarily placed in their order or importance. This would be difficult to do, as the relative importance of factors may differ for different antigens and histochemical procedures.

As far as can be determined, there appear to be no definitive articles that unequivocally show that IHC reactions are stoichiometric. In most laboratories, it is impractical to accurately determine section thickness, and furthermore many of the image analysis systems used may be somewhat rudimentary. Accurate determination of section thickness may therefore be somewhat of a moot point.