Venipuncture-related Stress in Dogs and Evaluation of the Fear Free™ FAS Scale as a Non-Invasive Stress Measurement Tool for Dogs in the Veterinary Hospital

Recognizing and measuring stress quickly and non-invasively in the veterinary context is desirable for guiding interventions to improve canine health and welfare during the provision of veterinary care. The Fear Free™ Fear, Anxiety and Stress (FAS) Scale serves this purpose but is not validated. We collected behavioral and physiological measures (urine cortisol:creatinine ratios, heart rate, and heart rate variability) of stress in 40 privately-owned dogs visiting a Fear Free Certified™ veterinary hospital for venipuncture with a credentialed technician. Visits were video-recorded to code 11 observable behaviors and score stress using the FAS Scale and Clinic Dog Stress Scale 1 (CDSS). There was moderate agreement between FAS and CDSS scores (73.78%, Cohen’s kappa = 0.55). While the number of intervals during which a dog experienced the venipuncture condition did not correlate with post-visit UCCR, veterinary visit duration was positively correlated with percent change in UCCR (rho = 0.34, p = 0.04) and post-visit UCCR was significantly higher than baseline UCCR (mean difference = 43.80, p = 0.0000051, 95% CI: 27.09 - 60.51). UCCR did not correlate significantly with FAS; however, max FAS scores were moderate to high for most dogs during venipuncture. Given the weak evidence for validity of the FAS Scale and moderate interobserver agreement (mean IOA = 76.04%), modifications to optimize the scale for clinical application should be considered, such as reduction of scoring to basic categorical levels (low, moderate, high), incorporation of arousal and emotional valence, focus on a single species with inclusion of visual references for common behavioral presentations of FAS, and more robust education and training in its use and application.