In order to perform immunostaining, tissue specimens should be preserved in an appropriate fixative.

IHC antigen retrieval reagent (citrate, pH 7.0) is used to recover antigens masked by because fixation in cross linking fixatives such as formalin

IHC antigen retrieval reagent (citrate, pH 8.0) is used to recover antigens masked by because fixation in cross linking fixatives such as formalin.

IHC antigen retrieval reagent (EDTA, pH 8.0) is used to recover antigens masked by over fixation in cross linking fixatives such as formalin.