Poor reproducibility of template bleeding time in horses.
Authors: Segura D, Monreal L
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Template Bleeding Time in Horses Segura and Monreal (2008) investigated whether template bleeding time (TBT)—a surgical bleeding test commonly used to assess platelet function and evaluate antiplatelet medication effects—performs reliably in equine clinical practice, drawing on evidence from human medicine suggesting the test lacks reproducibility. Testing twenty healthy horses with repeated measurements at baseline, 2 hours, and 30 days post-baseline, plus measurements following intravenous etamsylate administration, the researchers found coefficients of variation ranging from 26.8% to 45.5% between replicate measurements, with an impractically wide reference range of 138.4–860.4 seconds, despite no significant statistical differences between timepoints. Critically, etamsylate—an agent expected to reduce bleeding time—produced no statistically significant effect on TBT values, indicating insufficient sensitivity to detect genuine pharmacological changes in platelet function. Given these findings, equine practitioners should exercise considerable caution when interpreting TBT results in clinical diagnostics; the test's poor reproducibility and insensitivity mean individual results carry limited reliability for guiding treatment decisions regarding suspected coagulopathies or monitoring drug responses. Alternative haemostatic assessments with superior reproducibility warrant investigation and adoption for more robust evaluation of platelet dysfunction in horses.
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Practical Takeaways
- •Template bleeding time should not be relied upon for diagnosing platelet function disorders in horses due to poor reproducibility and wide reference range
- •Etamsylate's effect on platelet function cannot be assessed using TBT; alternative coagulation tests should be considered
- •Equine practitioners should request alternative platelet function tests with better reproducibility when investigating bleeding disorders or drug effects
Key Findings
- •Template bleeding time coefficients of variation ranged from 26.8% to 45.5%, indicating poor reproducibility
- •Reference range for TBT was 138.4-860.4 seconds, which is too wide for clinical utility
- •No statistically significant shortening of TBT was observed after etamsylate administration
- •TBT has insufficient sensitivity to detect platelet function effects in horses