Association of the neutrophil-lymphocyte ratio with outcome in sick hospitalized neonatal foals.
Authors: Samuels Amanda N, Kamr Ahmed M, Reed Stephen M, Slovis Nathan M, Hostnik Laura D, Burns Teresa A, Toribio Ramiro E
Journal: Journal of veterinary internal medicine
Summary
# Neutrophil-lymphocyte ratio as a prognostic indicator in sick neonatal foals The neutrophil-lymphocyte ratio (NLR)—calculated by dividing absolute neutrophil count by absolute lymphocyte count—offers clinicians an objective, readily available biomarker for predicting survival outcomes in hospitalised neonatal foals. Samuels and colleagues conducted a retrospective analysis of complete blood count data from 993 sick foals under 4 days old across three equine referral centres, stratifying animals by sepsis status and survival outcome to evaluate whether admission NLR values correlated with nonsurvival. Hospitalized foals demonstrated markedly depressed NLRs compared to healthy neonates (median 3.55 versus 6.61), with septic foals showing the most severe suppression (2.00); critically, nonsurviving foals exhibited substantially lower ratios (1.97) than their surviving counterparts (4.10), and foals with admission NLR values below 3.06 or below 1.6 carried 3.2-fold and 4.0-fold increased odds of nonsurvival, respectively. These findings suggest that NLR assessment—a simple calculation derived from routine haematological samples—provides clinically actionable prognostic information at the point of admission, potentially helping practitioners identify high-risk neonates who may warrant intensified or modified therapeutic approaches early in hospitalization.
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Practical Takeaways
- •Use NLR as an objective prognostic indicator in sick neonatal foals at admission—a low NLR (<3.06) suggests higher risk of nonsurvival and should prompt aggressive intervention
- •NLR is calculated from routine CBC results already performed on hospitalized foals, making it a cost-effective additional assessment with no extra laboratory work
- •Monitor NLR trends in septic foals particularly, as they show the poorest prognosis; consider this when discussing case severity and prognosis with owners
Key Findings
- •Neutrophil-lymphocyte ratio (NLR) was significantly lower in nonsurviving foals (1.97) compared to surviving foals (4.10)
- •Septic foals had the lowest NLR (2.00) compared to sick nonseptic foals (3.55) and healthy foals (6.61)
- •Foals with NLR <3.06 at admission had 3.21-fold increased odds of nonsurvival, while NLR <1.6 had 4.03-fold increased odds
- •NLR is a readily available, objective biomarker that provides clinically useful prognostic information in hospitalized neonatal foals