News & Resources

SAA – Stall Side Testing for Infection

Routine exams and temperatures are important ways to help determine if your horse is ill or may have an issue that affects performance.  These diagnostics are also a way equine health is evaluated for potential infectious diseases at the farm.  But a new test is available that is easy to perform and can be done right at the stall, the SAA.  This test is able to detect when inflammation is present in the horse even before the horse develops a fever or there are other blood work abnormalities such as increased white blood cell counts or fibrinogen. SAA is not affected by the administration of anti-inflammatories like bute or banamine.

SAA (Serum Amyloid A) is a simple blood test.  SAA is considered abnormal when it is above 20ug/ml.  SAA rises in response to infection with viruses and bacteria and is minimally, if at all, affected by exercise, anesthesia or stress.  In a study looking at horses after transportation, SAA was able to correctly identify horses that were going to become sick 90% of the time when it was measured 24 hours after arrival.  Taking the temperature was predictive about 3% of the time.  Measuring SAA could allow for earlier treatment preventing delays in training and performance and possible complications.

SAA may also be considered when trying to manage biosecurity issues.  While clear protocols still need to be worked out, isolating new horses with elevated SAA levels may help prevent the spread of disease on a farm. It can be used before co-mingling horses on a farm or to monitor horses at increased risk such as geriatric horses.  If there is an outbreak on a farm, it may help to identify horses before they show other signs of infection and allow for earlier intervention.

SAA can also help determine if a horse has a joint infection.  SAA levels rise quickly in blood when a joint is infected and there is evidence that SAA may also rise in joint fluid too.  Using SAA is useful if it is not possible to get fluid from the joint or in making decisions before the veterinarian leaves the farm.  

SAA cannot answer every question, but it can be used as a valuable tool in predicting illness and monitoring patient treatment.  A normal SAA does not necessarily mean the horse does not have a problem, but certainly an elevated SAA deserves further investigation.

At Pine Bush Equine Services, we have SAA readers on all of our ambulatory vehicles.  This information, especially when used with a thorough physical examination, helps us determine if your horse may have an infectious disease while the veterinarian is still at your farm.  It can also be useful in monitoring your horse’s response to treatment.  If you have questions about this important tool, please do not hesitate to reach out to us.

Hultén C, Demmers S. Serum amyloid A (SAA) as an aid in the management of infectious disease in the foal: comparison with total leucocyte count, neutrophil count and fibrinogen. Equine Vet J 2002;34(7):693-698.

Oertly M, Gerber V, Anhold H, et al. The accuracy of serum amyloid A in determining early inflammation in horses following long-distance transportation by air, in Proceedings. Am Assoc Equine Pract 2017;63:460-461.