Serum amyloid A (SAA) is an equine acute phase response protein. In the blood of healthy horses, SAA concentration is very low, but it increases dramatically with inflammation. Circulating SAA concentrations may increase up to 1000-fold following inflammation, infection or tissue injury (i-iii). Due to the short halflife of SAA, changes in its concentration in blood closely reflect the onset of inflammation and, therefore, measurement of SAA is useful in the diagnosis and monitoring of disease and response to treatment. Increases in SAA concentration have been described in equine digestive, reproductive and respiratory diseases and following surgical procedures. Moreover, SAA has proven useful for detection of some subclinical pathologies that can disturb training and competing in equine athletes (i).

(i) Witkowska-Piłaszewicz O.D. et al. 2019. Serum amyloid A in equine health and disease. Equine Veterinary Journal 51: 293–298.
(ii) Jacobsen S., Andersen P.H. 2007. The acute phase protein serum amyloid A (SAA) as marker of inflammation in horses. Equine Veterinary Education 19: 38–46.
(iii) Nunokawa Y. et al. 1993. Evaluation of serum amyloid A as an acute-phase reactive protein in horses. Journal Veterinary Medical Science 55; 1011–1016.