Immunohistochemical stains

What is it immunohistochemistry?

Immunohistochemistry (IHC) is considered an advanced form of histopathology. Immunohistochemistry is generally not used initially, but is added when routine / regular histological the test is insufficient to form a diagnosis.

IHC uses primary antibodies to tag a protein, then use a secondary antibody which is linked to the primary. In immunoperoxidase staining, an antibody binds to a enzyme, peroxidase, which catalyzes a reaction in which the protein specifically stains brown. IHC can also involve fluorescently labeled antibodies so that when viewed under a light microscope a certain pattern is observed from the emitted fluorescence.

The IHC pattern is considered diagnostic, which shows nuclear, membranous or cytoplasmic patterns. IHC is often used in situations where the presence or absence of certain proteins can form a basis for a diagnosis. It can also be used to distinguish between two different disease processes that might otherwise appear similar to pathologist.

How is immunohistochemistry performed?

The most common process for preparing immunohistochemical slides is as follows:

1. Tissue fixation (in general, IHC stains are fixed with formalin)
2. Embedding the tissue (in paraffin)
3. Sectioning of tissues.
4. Recovery (done with the application of heat or proteolytic enzymes)
5. Assembly and dehydration.
6. Cleaning and observation of the slides.

What are the advantages and disadvantages of immunohistochemistry?

The advantages of IHC include:

• Fresh or frozen tissue samples can be used for IHC.
• IHC is well established and readily available.
• The cost of IHC is relatively low
• It has a fast response time.
• Because no live infectious agents are involved, the risk to human health is minimal.

The disadvantages of IHC are as follows:

• IHC stains are not standardized throughout the world.
• Although the cost of the procedure is relatively inexpensive, the equipment required to perform IHC is expensive.
• Quantifying the results is difficult.
• IHC is subject to human error. Well-trained staff is paramount.

What are some examples of immunohistochemical stains?

Hundreds of immunohistochemical stains are used to identify different tumors and other neoplasms. Only some of the IHC stains used in dermatology they are listed below.