Acute phase protein (APP) assays are part of a toolbox of well proven biomarkers of inflammation and companion and large animals. Much of this information is translatable to small exotic companion animals and non-domesticated mammals. While avian and reptile species express APP, standard reagents do not readily cross reactive which has led to the validation of additional biomarker tests. This presentation will move from a general introduction of the biology of APP to their known utilities and onto the implementation in non-traditional species with examples of situational applications and goals for future assay development.