Assessment of a platelet function analyser in horses: reference range and influence of a platelet aggregation inhibitor.
Authors: Segura D, Monreal L, Espada Y, Pastor J, Mayós I, Homedes J
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary The PFA-100, a rapid platelet function analyser designed for human use, has been evaluated for its applicability in equine practice, with researchers establishing reference ranges and assessing its ability to detect pharmacologically-induced platelet dysfunction. Using citrated blood samples from 40 healthy horses, Segura and colleagues determined closure time (CT) values with collagen-ADP and collagen-epinephrine cartridges, then verified the device's sensitivity by measuring changes following oral acetylsalicylic acid (ASA) administration in a separate cohort of 12 horses. Baseline CT-ADP values averaged 85.1 seconds (reference range 60.5–115.9 s), whilst CT-EPI showed considerably prolonged times with a median of 291 seconds; crucially, ASA administration significantly extended CT-ADP by approximately 22.5 seconds and CT-EPI values similarly increased, demonstrating the device's capacity to detect platelet aggregation inhibition with high sensitivity and specificity. For equine practitioners considering antiplatelet therapy—whether for thrombotic prophylaxis, laminitis management, or other clinical indications—the PFA-100 offers a practical in-vitro method to assess primary haemostasis and verify drug efficacy, though the wide reference range for CT-EPI suggests this parameter may be less clinically useful than ADP-based measurements. The establishment of equine-specific reference ranges removes a significant barrier to adopting this technology in equine practice, enabling more objective evaluation of platelet function when clinical circumstances warrant antiplatelet intervention.
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Practical Takeaways
- •The PFA-100 with ADP cartridges can reliably assess platelet function in horses, providing a standardized test for haemostatic screening in practice
- •If treating horses with acetylsalicylic acid or other antiplatelet drugs, prolonged closure times on the PFA-100 indicate successful platelet inhibition, confirming adequate drug effect
- •This test may help identify horses at risk of bleeding disorders or assess coagulation status before surgery, though results should be interpreted alongside clinical signs
Key Findings
- •PFA-100 reference ranges established for horses: CT-ADP 60.5-115.9 s (mean 85.1±13.1 s) and CT-EPI 158.5->300 s (median 291 s)
- •Acetylsalicylic acid significantly prolonged CT-ADP from 91.0±13 to 113.5±14.4 s (P<0.001) and CT-EPI (P<0.008)
- •ADP cartridges demonstrated high sensitivity and specificity for detecting platelet aggregation inhibition in horses
- •PFA-100 is a valid tool for assessing primary haemostasis and detecting antiplatelet drug effects in equine patients