Evaluation of a commercially available apparatus for measuring the acute phase protein serum amyloid A in horses.
Authors: Jacobsen S, Kjelgaard-Hansen M
Journal: The Veterinary record
Summary
# Editorial Summary: Reliability of Commercial SAA Testing in Equine Practice Jacobsen and Kjelgaard-Hansen evaluated whether a commercially available immunoturbidometric assay could reliably measure serum amyloid A (SAA)—a key acute phase protein used to detect inflammation in horses—comparing it against an established reference method across healthy and diseased animals. Intra-assay variation ranged from 4.6–11.7% depending on SAA concentration (low vs high pools), with interassay variation of 5.6–9.1%, indicating acceptable reproducibility for clinical use; whilst the apparatus systematically underestimated SAA concentrations relative to the validated reference method, this bias remained negligible compared to the magnitude of SAA elevation seen in disease states. The assay successfully discriminated between clinically healthy horses and those with inflammatory or non-inflammatory conditions, making it suitable for identifying active inflammation in practice. These findings support the use of this point-of-care or laboratory-based apparatus as a practical tool for practitioners seeking rapid SAA measurements to guide diagnosis and monitor treatment response, though practitioners should be aware the device provides conservative estimates and should interpret results within the clinical context rather than relying on absolute values alone.
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Practical Takeaways
- •This commercially available SAA assay is suitable for clinical practice as it reliably distinguishes between healthy and diseased horses despite systematic underestimation
- •The assay's acceptable precision (especially at high SAA levels relevant to acute inflammation) makes it practical for detecting inflammatory conditions in horses
- •Practitioners should be aware the assay tends to underestimate actual SAA values, though this does not impair its clinical utility for diagnosis
Key Findings
- •Immunoturbidometric assay for serum amyloid A showed intra-assay coefficients of variation of 11.7% (low SAA) and 4.6% (high SAA)
- •Interassay coefficients of variation were 9.1% (low SAA) and 5.6% (high SAA), demonstrating acceptable reproducibility
- •The assay systematically underestimated SAA concentrations compared to a validated reference assay
- •Despite slight inaccuracies, the assay reliably detected expected differences in SAA between healthy and diseased horses