Antigen retrieval methods include HIAR and enzymatic (protease-induced) which is not further discussed here. HIAR using either a microwave oven or a pressure cooker is a common approach as they typically have a higher success rate for restoring antigenicity than an enzymatic method. We provide sample protocols below of HIAR with a microwave oven or a pressure cooker (Decloaking chamber, (Biocare Medical, Pacheco, CA, USA)). Other pressure cookers may use different protocols and manufacturer instructions should be followed. It is emphasized that only one HIAR method need be utilized- not both microwave and pressure cooker.