Immunohistochemistry is a technique used to visualise cellular antigens (usually proteins) and infectious agents using specific antibodies within tissue sections. It is routinely used in diagnostic histopathology to assist in providing a more definitive diagnosis and, with regards to neoplasia, prognostic information.

At Finn Pathologists we provide a comprehensive immunohistochemistry service to clients. We have developed and validated a wide range of cell markers to assist with tumour diagnostics and prognostication in dog and cat tissues. Following the examination of routinely stained histological sections, pathologists will advise if immunohistochemistry can be undertaken to further the diagnosis.


CD3 Stain of a canine peripheral high grade lymphoma with a strong positive reaction.
CD79a Stain of a canine peripheral high grade lymphoma with a negative reaction (positive cells are residual B cells).
PAX-5 Stain of a canine peripheral high grade lymphoma with a negative reaction (positive cells are residual B cells).

Using panels of specific antibodies we are able to provide additional information with regards to the cell of origin in cases of neoplasia, particularly when there is a confusing picture on routine sections. By providing a more definitive diagnosis this allows veterinary practitioners to progress cases using up-to-date appropriate therapies. It should be noted that, as tumour cells can have altered expression of certain antigens, it is possible that immunohistochemistry results may still not be conclusive, but it can also be a very useful tool to assist in excluding some of the potential differential diagnoses in a poorly differentiated neoplastic lesion.

In cases where infectious agents are suspected it is possible to confirm their presence using specific immunohistochemistry antibodies. This is particularly useful in many large animal diseases such as viral pneumonia (e.g. PRRSV and swine influenza) and systemic diseases such as BVD.

We have access to a wide range of referral laboratories across the world that can provide us with additional immunohistochemistry based testing for the more unusual cases that require further investigation.

Our trained histology team produce sections that are examined by the pathologist who initially dealt with the case, where possible, to ensure full interpretation of the immunohistochemistry can be made based upon the clinical history and routine sections. Our pathologists are happy to discuss the application of immunohistochemistry and the significance of any findings following case review.

The laboratory participate in external quality assurance schemes to ensure continued high standards. We have an immunohistochemistry development team who oversee the day-to-day quality issues surrounding testing and who review the literature to ensure we remain at the forefront of new developments. We are also constantly updating our antibody panels to suit the needs of our client base, e.g. development of in-house equine immunohistochemistry testing.