Serum amyloid A as a marker to detect sepsis and predict outcome in hospitalized neonatal foals.
Authors: Hoeberg Emma, Sånge Alexandra, Saegerman Claude, Bohlin Anna, Nostell Katarina, Durie Inge, Husted Louise, Öhman Anna, Jacobsen Stine, Berg Lise, Laursen Sigrid Hyldahl, van Galen Gaby
Journal: Journal of veterinary internal medicine
Summary
# Serum Amyloid A in Neonatal Foal Sepsis: Diagnostic and Prognostic Value Sepsis remains a major cause of morbidity and mortality in hospitalised neonatal foals, yet early detection and prognostication remain challenging. This retrospective multicenter study of 590 foals under 14 days old investigated whether admission serum amyloid A (SAA) concentrations could reliably identify septic foals and predict survival outcomes. Septic foals demonstrated significantly elevated SAA levels (mean 1079.7 mg/L) compared to sick non-septic foals (312.1 mg/L), with concentrations rising proportionally to sepsis severity scoring, though SAA did not discriminate between sepsis severity categories. An optimal cut-off value of 1050 mg/L provided 90.7% specificity but only 30.2% sensitivity for sepsis detection; similarly, a cut-off of 1250 mg/L predicted non-survival with 90.8% specificity and 22.1% sensitivity. This high specificity with low sensitivity makes SAA particularly valuable as a rule-out marker—a normal or moderately elevated value effectively excludes sepsis and suggests a favourable prognosis, whereas markedly elevated SAA warrants serious concern but cannot be used in isolation to confirm sepsis or mortality risk. Clinicians should integrate SAA into a broader diagnostic approach alongside clinical parameters and other inflammatory markers rather than relying on it as a standalone diagnostic test.
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Practical Takeaways
- •SAA has high specificity for ruling out sepsis and predicting nonsurvival in neonatal foals, making it useful as a negative prognostic marker rather than diagnostic confirmation
- •Low sensitivity values mean SAA should not be used alone to diagnose sepsis or predict survival; it should complement clinical assessment and other diagnostic markers
- •Elevated admission SAA concentrations (>1250 mg/L) warrant careful prognosis discussion with owners, though clinical judgment remains essential
Key Findings
- •Admission SAA concentrations were significantly higher in septic foals (1079.7 mg/L) compared to sick nonseptic foals (312.1 mg/L)
- •SAA increased with increasing sepsis score but did not differ between sepsis severity groups
- •Optimal SAA cut-off of 1050 mg/L for sepsis detection had low sensitivity (30.2%) but good specificity (90.7%)
- •Nonsurviving foals had higher admission SAA (1062.7 mg/L) than surviving foals (435.0 mg/L), with optimal cut-off of 1250 mg/L for nonsurvival prediction showing 22.1% sensitivity and 90.8% specificity