Investigation of the Use of Serum Amyloid A to Monitor the Health of Recently Imported Horses to the USA.
Authors: Middlebrooks Brittany Tuttle, Cowles Bobby, Pusterla Nicola
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Serum Amyloid A as a Health Screening Tool in Recently Imported Horses Serum amyloid A (SAA) is an acute phase protein that rises rapidly during inflammation and infection, making it an attractive candidate for early detection of subclinical disease in at-risk populations such as recently imported horses. Researchers retrospectively analysed archived serum samples from 143 European horses shortly after arrival at a US quarantine facility, stratifying them into healthy (n=109), subclinically inflamed based on haematological markers (n=30), and clinically sick (n=4) groups to evaluate whether SAA values could discriminate between these categories. SAA concentrations showed considerable overlap across all groups, with healthy and subclinically inflamed horses displaying nearly identical median values (9 µg/mL each) despite wide ranges, whilst sick horses exhibited a higher median (590 µg/mL), though notably three of four sick horses were the only ones with markedly elevated results. The inability to establish a reliable diagnostic threshold—or indeed to determine the underlying cause of elevated SAA in most horses with raised values—substantially limits the clinical utility of single-point SAA testing as a supplementary screening tool during the quarantine period. For practitioners managing recently imported stock, this finding suggests that conventional clinical examination and haematological assessment remain the evidence-based foundation for health monitoring, with SAA measurement offering no additional diagnostic advantage in this specific context.
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Practical Takeaways
- •SAA alone is not a reliable screening tool for identifying subclinical disease in newly imported horses—rely on traditional clinical examination and complete blood work instead
- •High background SAA values in apparently healthy imported horses may reflect transport stress or occult infections; serial testing rather than single samples may be needed if SAA monitoring is desired
- •Continue standard quarantine protocols and hematological assessment as primary tools for health evaluation of newly arrived horses rather than adding SAA testing to the routine
Key Findings
- •SAA values were similarly elevated in both healthy horses (median 9 µg/mL, range 0-3,000) and horses with subclinical inflammation (median 9 µg/mL, range 0-1,522), limiting discriminatory value
- •Only 3 of 4 sick horses showed elevated SAA (median 590 µg/mL), indicating low sensitivity for clinical disease detection
- •The majority of elevated SAA values in healthy and subclinically inflamed horses could not be attributed to identified causes
- •Single point-in-time SAA testing did not provide additional diagnostic value beyond routine clinical and hematological monitoring