Histopathology Services

Histopathology is the microscopic examination of tissue for disease.  Toxikon offers a wide variety of  histopathology testing services.

Understanding Histopathology Testing Services

Digital Pathology

As an evaluation end point of certain studies, digital pathology including digital staining, residual implant material remaining and other analyses are required. Digital pathology also includes slide scanning and the sharing of slides over the cloud removing the necessity for physical slides to be present for the pathologist

Tissue Processing and Staining Expertise

Our team has vast experience in both large and small animal necropsy and tissue processing. We can process whole tissues and biopsies and have extensive experience in hard, soft and ocular tissues. Both routine and special staining can be performed to fit the nature of the tissue and study being analyzed. Our histology team and pathologists can work with you to develop your evaluation requirements.


In certain cases, it’s necessary to perform microphotography in order to explain better pictorially a specific cellular reaction or structure type. The photographs are taken using Olympus microscopes with attached cameras and can be performed in support of Toxikon projects or as a standalone service.

Hematoxylin & Eosin Staining

Biological tissue has little inherent contrast in either the light or electron microscope. The staining process gives contrast to the tissue as well as highlighting particular features of interest. The hematoxylin and eosin staining, commonly referred to as H&E, is considered the “routine” tissue staining method for light microscopy evaluation. It colors nuclei of cells and a few other objects, such as keratohyalin granules blue, followed by counterstaining with an aqueous or alcoholic solution of eosin which colors cytoplasm and eosinophilic structures in various shades of red, pink, and orange for initial microscopic evaluation of tissues. Eosin Y is routinely used as the counter stain in H&E staining in our laboratory.

Special Staining

Special stain adequately reveals certain structural components of histological section such as basement membranes, reticular fibers, and lipids, etc. It is usually considered when these cells or cellular components are selectively stained by other techniques and dyes. There are hundreds of various techniques and dyes employed in special staining, and they are usually employed in specific situations according to diagnostic need.

Special stains are “special” because they are not routine. They are applied to tissue sections in addition to H&E stained sections to answer questions that arise above and beyond those that can be answered by interpreting H&E stained tissue morphology. A variety of dyes and techniques are used in special stains to stain particular tissues, structures or pathogens including, but not limited to, carbohydrates, amyloid, connective tissue, muscle tissues, nerves, lipids, bones, microorganisms, pigments, minerals, cytoplasmic granules, and organelles.
The commonly performed special stains in this lab are Periodic Acid Schiff stain (PAS), Alcian blue, Masson trichrome stain, Giemsa, modified Diff-Quik, Gram, Safranin O, Cresyl echt violet, Silver stain, Luxol fast blue, Acid-fast stain, Methenamine silver nitrate, and Prussian blue stain.


Immunohistochemistry staining (IHC) refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies (Abs) which bind specifically to antigens in biological tissues. Immunohistochemical staining is widely used in the diagnosis and basic research to understand the distribution and localization of biomarkers and differentially expressed proteins in different parts of a biological tissue.

The procedures will include, some or all, but not limited to, the following steps: selection of proper controls (positive and negative), deparaffinization, antigen retrieval, endogenous enzyme blocking, primary Abs, secondary Abs, detection, visualization, counter stain, dehydration, coverslipping.

Pathology Evaluation

Histopathology evaluation is performed by our staff of pathologists with expertise in biocompatibility, toxicology, ocular and surgical model studies. We will work with you to develop a protocol and evaluation criteria for your study that will fit specific requirements.