Laura C Chadwick
Vice President, Life Diagnostics, Inc.
CEO Veterinary Biomarkers, Inc.
The significance of acute phase proteins (especially SAA) in the diagnosis of animal diseases
Acute phase protein (APP) levels increase in blood and other bodily fluids as a result of inflammation, tissue injury and disease. They are used as biomarkers in humans, companion animals, livestock and species used in preclinical research. There has recently been increased availability of assays for use in veterinary diagnostic laboratories. Point of care testing, while not incredibly sensitive or quantitative, is now available worldwide for dog C-reactive protein (CRP), bovine Haptoglobin and cat Serum Amyloid-A (SAA). When selecting an acute phase biomarker, it is important to appreciate that a good biomarker in one species is not necessarily useful in other species. For example, CRP can increase as much as 1000-fold in humans and dogs, but it increases by only 50% in rats; and there is found to be only a minimal increase in cats. Serum Amyloid-A is a positive acute phase reactant synthesized in the liver that circulates in blood mostly associated with high density lipoprotein (HDL). In cats, basal serum levels can increase several hundred-fold because of infection, disease, metabolic syndrome or cancer. Therefore, SAA as opposed to CRP, should be the APP of choice in cats. SAA has proven to be a valuable marker in other species as well. It has shown to be useful in the diagnosis of mastitis in cows and multitude of applications in horses including sports performance, monitoring pregnancy, diagnosing colic and monitoring post-surgery complications. Overall, the expanding veterinary literature points to the utility of SAA monitoring as part of animal annual wellness exams as well as it being a sensitive prognostic tool for disease states.
It is also important to use an assay that has been demonstrated to perform in the targeted species. Acute Phase Proteins are not highly conserved. Having the correct tools, such a species-specific assay, is paramount when using APPs as a diagnostic tool. Life Diagnostics, Inc. was founded in 1997 with the intention to address this issue and to fill the void presented by the lack of test kits for measurement of cardiovascular and acute phase protein biomarkers in species used in veterinary and preclinical research. As a research driven organization, we constantly strive to address the needs of both the research and clinical community. Being on the forefront of APP assay development, we have worked over the past two decades to create a catalog of close to 200 ELISA kits and over 100 SPARCL assays. We provide kits with unparalleled sensitivity, allowing for identification of subclinical cases. Our long-term goal is to provide better tools for veterinary diagnostics.