United Kingdom researchers recently reported that endoscopic examinations of upper airway obstructions in horses at rest and without the use of a treadmill can be unreliable and should not be used alone to diagnose conditions and determine treatment.

Often, endoscopic exams are major factors in the decision to purchase a horse or if a surgical procedure is necessary. However, researchers at the University of Bristol said if the horse was examined at rest, the results can be unreliable.

They concluded, “Endoscopy of the upper respiratory tract of static horses is unreliable in the diagnosis of dynamic obstructions of the upper respiratory tract and should not be used in isolation in surgical decision-making or in the assessment of horses at the time of sale.”

Reseachers looked at 600 Thoroughbreds that were brought to the university with owner or trainer complaints of poor performance. They compared diagnoses of horses at rest with diagnoses of horses examined while on the treadmill, and they found that horses were commonly misdiagnosed when they were examined at rest. Researchers said resting endoscopy had a high specificity (how well it classifies abnormalities) but a low sensitivity (accuracy). The sensitivity was increased if the clinician was aware of the horse having a history of producing noises during exercise. However, not all horses that have palatal abnormalities produce such noises, which could limit the clinician’s diagnostic capability