Validation of the Ipswich Touch Test for Screening of Loss of Protective Sensation and Peripheral Neuropathy in Type II Diabetes

Introduction: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes that significantly increases the risk of foot ulceration and amputation. Early detection of loss of protective sensation (LOPS) is critical, particularly in resource-limited settings. This study aimed to validate the Ipswich Touch Test (IpTT), a simple and non-invasive screening tool, against the 10 g monofilament (MF) and other neurological assessments in individuals with Type II diabetes. Methods: A cross-sectional study was conducted among Type II diabetic patients from the XXX Diabetes (SeDia) Cohort. Participants underwent foot examinations using MF (reference standard), IpTT, and pinprick, vibration, and ankle reflex tests. Sensitivity, specificity, predictive values, likelihood ratios, and agreement (kappa coefficient) were calculated. Results: Among 315 participants, the prevalence of LOPS/DPN was 14.6%. IpTT demonstrated 90.5% accuracy, with a sensitivity of 41.3% and specificity of 98.9% compared to MF. Agreement between IpTT and MF was moderate (κ = 0.513, p < 0.001). Vibration testing had the highest sensitivity, while pinprick showed the best specificity. Ankle reflex testing performed poorly. Conclusion: IpTT is a highly specific and accurate screening tool suitable for use in low-resource settings. Despite limited sensitivity, it is a valuable adjunct to other neurological tests in detecting LOPS and DPN.