Neutrophil Gelatinase-Associated Lipocalin in Synovial Fluid from Horses with and without Septic Arthritis.
Authors: Jacobsen Stine, Mortensen Camilla Drejer, Høj Elisabeth Alkærsig, Vinther Anne Mette, Berg Lise Charlotte, Adler Ditte Marie Top, Verwilghen Denis, van Galen Gaby
Journal: Animals : an open access journal from MDPI
Summary
# Neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker for equine septic arthritis Septic synovitis in horses demands rapid, accurate diagnosis to guide urgent treatment, yet distinguishing infection from sterile joint inflammation remains clinically challenging. Researchers measured NGAL concentrations in synovial fluid from 177 admission samples (152 horses) and sequential treatment samples from 35 horses, comparing those with confirmed septic arthritis, non-septic conditions, and uncertain diagnoses. NGAL concentrations were dramatically elevated in septic cases (median 1236 µg/L) compared to non-septic samples (16.8 µg/L), with near-perfect discrimination between these groups (ROC AUC 0.98); when differentiating septic from uncertain cases, an optimal cut-off of 444.6 µg/L achieved 87.2% sensitivity and 75.0% specificity. Crucially, NGAL levels declined progressively during treatment, indicating potential utility for monitoring therapeutic response. This biomarker offers equine practitioners a novel diagnostic tool with exceptional specificity for confirming septic arthritis at admission whilst also providing an objective means to assess treatment efficacy over time—particularly valuable when clinical improvement alone is ambiguous.
Read the full abstract on PubMed
Practical Takeaways
- •NGAL is a highly accurate biomarker that can help definitively identify septic arthritis in horses, reducing diagnostic uncertainty compared to traditional synovial fluid analysis alone
- •NGAL levels can be tracked during treatment to objectively monitor response to therapy and guide clinical decision-making regarding duration of treatment
- •A cut-off value of 444.6 µg/L can help distinguish confirmed septic cases from questionable or borderline cases when initial diagnosis is unclear
Key Findings
- •NGAL concentrations in septic synovitis samples (median 1236 µg/L) were significantly higher than non-septic samples (16.8 µg/L) and uncertain status samples (266.4 µg/L)
- •NGAL discriminated nearly perfectly between septic and non-septic samples with AUROC of 0.98 (95% CI 0.95-1.00)
- •Optimal cut-off value of 444.6 µg/L discriminated septic from uncertain status samples with 87.2% sensitivity and 75.0% specificity
- •NGAL concentrations declined over time in horses undergoing treatment for synovial infection