Which detection approach allows for double staining in IHC?

Which detection approach allows for double staining in IHC?

• A. Peroxidase and AP method (double staining)
• B. Polymer based detection method only
• C. HRP based method only
• D. ABC method only

Answer: (A)

Double staining relies on using two distinct enzyme systems so each target can produce a different color product. When one target is detected with a peroxidase reaction (for example, with DAB, which gives a brown deposit) and the other with alkaline phosphatase (using a different chromogen such as Fast Red), you can distinguish the two antigens in the same tissue because the colors stay separate. This approach is inherently suited for two colors in one staining run, assuming proper sequential steps and blocking to prevent cross-reactivity. The other methods described are typically set up for a single color per staining run, using one enzyme-substrate pair. They can be adapted to multiple rounds, but they don’t provide two distinct colors in a single, straightforward protocol as the combination of peroxidase and alkaline phosphatase does.

Double staining relies on using two distinct enzyme systems so each target can produce a different color product. When one target is detected with a peroxidase reaction (for example, with DAB, which gives a brown deposit) and the other with alkaline phosphatase (using a different chromogen such as Fast Red), you can distinguish the two antigens in the same tissue because the colors stay separate. This approach is inherently suited for two colors in one staining run, assuming proper sequential steps and blocking to prevent cross-reactivity.

The other methods described are typically set up for a single color per staining run, using one enzyme-substrate pair. They can be adapted to multiple rounds, but they don’t provide two distinct colors in a single, straightforward protocol as the combination of peroxidase and alkaline phosphatase does.