Bio Basic

Chromogens for IHC

Chromogens for IHC



Detection of antigens using a specific antibody requires a chromogen to visualize the target antigen. The type of chromogen used is determined by various factors such as:
  • The type of test
  • The level of expression of the antigen
  • If it is necessary to quantify or not the signal
  • The type of acquisition used
We offer a wide choice of specific chromogens for immunohistochemistry (IHC), for use with the 2 enzymes most used in this technique: horseradish peroxidase (HRP for Horseradish Peroxidase) and alkaline phosphatase (AP). Chromogens are chemical compounds used in IHC labeling procedures that produce a colored product that can be visualized by light microscopy. The choice of chromogen to use is directly related to the enzyme used in the test. Indeed, the enzyme will catalyze the conversion of the chromogenic substrate to produce a colored precipitate. Each enzyme can catalyze the conversion of specific substrates. Here are some examples of chromogens:

HRP:
  • Aminoethyl carbazole (AEC)
  • 3,3'-diaminobenzidine (DAB)
  • 3,3'5,5'-tetramethylbenzidine (TMB)
  • Emerald
AP:
  • Fast Red
  • Permanent Red
  • Mixture of nitro blue tetrazolium chloride (NBT) and 5-bromo-4-chloro-3-indolyl phosphate (BCIP) (NBT / BCIP)