Serum amyloid A as an aid in diagnosing sepsis in equine neonates

Background Sepsis is a significant cause of morbidity and mortality in neonatal foals, especially during the first 7 days of life. Diagnosing sepsis in neonatal foals can be challenging because initial clinical signs are often ambiguous and non-specific. Objectives To determine if the major acute phase protein serum amyloid A (SAA) as measured by a point-of-care SAA testing device can be used as an evidence-based biomarker of sepsis. Study design Retrospective cohort. Methods Clinical diagnosis of sepsis based on positive bacterial blood culture or a positive sepsis score was obtained and compared to SAA values in a population of neonatal foals on a breeding farm and referral hospital during four consecutive foaling seasons. A rapid, point-of-care blood test was used to measure SAA concentrations in neonatal foals <36 hours old that were clinically diagnosed as healthy, sick non-septic or septic. Results The septic foals (n = 35) had a median SAA concentration (114 mu g/mL) that was significantly greater (P < .05) than that for foals in the sick non-septic (n = 117, 1.5 mu g/mL) and healthy (n = 245, 0 mu g/mL) groups. At a diagnostic threshold of 100 mu g/mL, the SAA test had a sensitivity of 52.9% (95% CI 36.5-68.9), specificity of 97.5% (95% CI 95.0-99.0), positive predictive value of 75.0% (95% CI 56.2-87.5), negative predictive value of 93.7% (95% CI 91.2-95.5), and a test accuracy of 92.1% (95% CI 88.2-95.0). Conclusions The results of this study indicate that SAA is a useful aid in the diagnosis of sepsis in the neonatal foal.