Whole-Blood Validation of a New Point-of-care Equine Serum Amyloid A Assay

Serum amyloid A (SAA) is considered a major acute phase protein (APP) in horses. Serum amyloid A stall-side assays are commercially available to assess the inflammatory response of patients with various infectious and noninfectious conditions. The objective of this study was to determine the analytical performance of a new point-of-care (POC) assay for the measurement of SAA in whole blood and plasma of horses. One hundred and sixty blood samples were collected from 60 horses at various time points after immunization with an equine core vaccine. Analytical validation of the SAA POC assay included the measurement of SAA in whole blood and plasma, assessment of linearity and precision, and comparison of the SAA POC results with those obtained with a validated turbidimetric immunoassay (TIA). The SAA POC assay yielded similar results in whole blood and plasma (P > .05), and the results were positively correlated with the TIA (R² = 0.964). The assay displayed solid linearity throughout the detection range of ≤ 20 to 3,000 μg/mL (R² = 0.984) with inter-assay and intra-assay coefficients of variation ranging from 7.8% to 13.3% and 5.7% to 12.0%, respectively. The new SAA POC assay was able to reliably measure SAA in both whole blood and plasma. Similar to previously validated assays, the new SAA POC assay is a valuable tool to investigate the inflammatory response in various clinical diseases of horses.