Enhancement of immunoreactivity among lymphoid malignant neoplasms in paraffin-embedded tissues by refixation in zinc sulfate-formalin.

Abstract

It has been previously demonstrated that improved cytomorphologic detail can be obtained from tissue blocks initially fixed in 4% formaldehyde solution by means of a "run-back" procedure to an aqueous phase of solution, allowing refixation with a protein-precipitating agent, such as zinc sulfate-4% formaldehyde solution. Because anecdotal experience with immunostaining such reprocessed tissues had suggested improved results, we performed a prospective trial involving 13 cases to compare the intensity of immunoreactivity before and after such reprocessing. In 10 of 13 cases studied with a variety of antibody reagents, we noted a definite improvement of staining, preferentially among those with the weakest original immunoreactivity.