Upper image after TRIS ph10 HIER. Lower image after Citric acid pH6 HIER.

One should try the range of HIER/HIAR  solutions to ensure you use the best, for your laboratory.

Do not assume that any one solution is optimal for all antibodies. Sometimes only proteolytic AR works.

Sometimes only frozen sections work.

Sometimes Formalin on frozen sections does not work…try acetone or Methanol or 1:1 of those two.