Methods used in clinical laboratory diagnosis in the veterinary laboratory closely parallel the common techniques used in the human laboratory. Immunology procedures include immunohematology, autoimmune testing, and assays for detection of immune deficiencies and infectious diseases. Veterinary immunohematology procedures deal with immune-mediated hemolysis, as well as blood typing, cross matching, and transfusion.

Diseases of the immune system in animals include rheumatoid arthritis, systemic lupus erythematosus (SLE), and immunodeficiency disorders. The number of infectious diseases that can be diagnosed in a veterinary laboratory is almost limitless, but perhaps two of the most prevalent and significant are heartworm disease and feline infectious peritonitis (FIP).