Immunoreactivity of canine, feline, and equine D-dimer with antibodies to human D-dimer.
Authors: Brown Juliet E, Noormohammadi Amir H, Courtman Natalie F
Journal: Journal of veterinary internal medicine
Summary
D-dimer assays are commonly used in veterinary practice to assess coagulation and thromboembolic risk, yet they rely on antibodies designed against human D-dimer with largely unvalidated performance in animals. Brown and colleagues systematically evaluated how five different commercial antibodies—both monoclonal and polyclonal—recognised D-dimer across canine, feline, and equine plasma samples using immunoblotting techniques. Results revealed striking species-dependent variation: the monoclonal antibody DD44 showed robust reactivity with canine D-dimer but failed entirely to bind feline or equine D-dimer, whilst the polyclonal antibody D2D demonstrated cross-species recognition with notably higher sensitivity in dogs, cats, and horses compared to human D-dimer standards. This work explains why D-dimer assay performance differs substantially between species and underscores the critical need for species-specific validation before clinical adoption. For equine practitioners specifically, the findings suggest that current commercial assays may deliver unreliable results in horses; pending development of validated equine-specific assays, results should be interpreted with considerable caution and correlated with clinical and imaging findings rather than used as standalone diagnostic markers.
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Practical Takeaways
- •Commercial D-dimer assays designed for humans may have unreliable results in horses and other companion animals—results should be interpreted with caution until species-specific assays are validated
- •Equine practitioners should advocate for species-specific D-dimer assays before relying on these tests for clinical decision-making regarding thromboembolism or coagulation disorders
- •Current limitations suggest D-dimer testing in equine patients requires validation studies and careful interpretation of results in clinical practice
Key Findings
- •Monoclonal antibody DD44 demonstrated good specificity and sensitivity for canine D-dimer but showed no reactivity with feline or equine D-dimer
- •Polyclonal antibody D2D bound putative D-dimer in dogs, cats, and horses with good specificity and higher sensitivity compared to human D-dimer
- •Commercially available human D-dimer assays show variable performance across species due to inter-species variation in D-dimer immunoreactivity
- •Species-specific validation studies are necessary before applying human D-dimer assays in veterinary medicine