In traditional Chinese veterinary medicine, palpation of sensitive acupuncture points (scan diagnosis) is part of the equine clinical exam and is routinely used to locate pain and/or structural disease. The objective of this double-blinded study was to evaluate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of scan diagnosis and its correlation with conventional diagnostic methods. In addition, the diagnostic acupoint’s reactivity grade was compared to lesion severity to evaluate any correlation between the 2 methods of disease diagnosis. Fifty-nine client-owned horses randomly chosen and presented for a variety of equine clinical diseases were included in the study. Performance statistics (sensitivity, specificity, PPV, NPV) of the scan diagnosis were calculated by comparison with the conventional exam outcomes. Study findings for scan diagnosis demonstrated a sensitivity of 88.7% (true positive rate), a specificity of 86.9% (true negative rate), NPV value of 98.1% (percentage of non-lesions determined by the scan diagnosis also shown negative in the conventional examination) and positive predictive value of 50.6% (percentage of lesions determined by the scan diagnosis also shown from conventional examination). In addition, a statistically significant correlation (p-value < 0.001) between acupuncture point reactivity grade and lesion severity was demonstrated. This study showed that the scan diagnosis might be a reliable and complementary tool when diagnosing equine pain and/or structural diseases.