Antigen retrieval (or antigen recovery) is performed to expose or retrieve antigens which have become masked by the tissue fixation process.

There are various protocols available. Some make use of heat induced epitope retrieval (HIER) while others apply enzymes.

The following antigen recovery protocol is microwave based. Studies have shown microwave antigen retrieval to be effective in unmasking epitopes in formalin fixed, paraffin wax embedded tissues.

1. Place slides in a plastic Coplin jar
2. Add citrate buffer - cover slides
3. Cover with a perforated film
4. Place Coplin jar into microwave
5. Microwave at medium power for 5 minutes
6. Add citrate buffer to replace evaporative losses
7. Microwave at medium for up to 5 minutes
8. Add more citrate buffer
9 . Allow slides to cool
10. Proceed with immunohistochemistry protocol