OPD, DAB & Fast RED Tablets2017-04-28T15:23:07+00:00


OPD Tablets for colorimetric detection of Horseradish Peroxidase activity in ELISAs.

Ortho-Phenylenediamine (OPD) is a water soluble chromogenic substrate that produces a yellow color during the enzymatic degradation of hydrogen peroxide by horseradish peroxidase (HRP) with an absorption maximum at 450 nm. After addition of sulfuric acid a very stable orange end solution is obtained that can be read at 490 nm.

Kem-En-Tec Diagnostics offers:

  • Fizzing OPD tablets: 2 mg tablets are available as fizzing, buffer-containing tablets (#4110-100)


Catalog number Tablet type Tablet size Package size
4110-100 Fizzing OPD tablets 2 mg 100 tablets/vial




FAST RED is a sensitive chromogenic substrate for use in immuno-histochemistry and immunoblotting procedures.

FAST RED offers an Alkaline Phosphatase immunostaining system which produces a red stain precipitate at the site of the antigens.

Each tablet contains:

  • 2 mg FAST RED chromogen
  • 0.5 mg naphthol phosphate
  • 0.4 mg levamisole (an inhibitor of endogenous enzyme activity).

1 tablet is dissolved in 2 ml of 0.1M TRIS Buffer.

Standard package size is 50 tablets/vial.


  • Stable and robust
  • Negligible batch-to-batch variation
  • Development time: 5-30 minutes


  • 18 -24 months at 2-8° C
  • For long term storage Fast Red tablets should be kept at -20°C


All products are available as OEM components or under our own Kem-En-Tec Diagnostics A/S label.

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