, Volume 51, Issue 6, pp 1046-1050
Date: 27 Mar 2008

The Neuropad test: a visual indicator test for human diabetic neuropathy



The commercially available Neuropad test was developed as a simple visual indicator test to evaluate diabetic neuropathy. It uses a colour change to define the integrity of skin sympathetic cholinergic innervation. We compared the results of Neuropad assessment in the foot with established measures of somatic and autonomic neuropathy.


Fifty-seven diabetic patients underwent Neuropad assessment, quantitative sensory and autonomic function testing, and evaluation of intra-epidermal nerve fibre density in foot skin biopsies.


Neuropad responses correlated with the neuropathy disability score (r s = 0.450, p < 0.001), neuropathic symptom score (r s = 0.288, p = 0.03), cold detection threshold (r s = 0.394, p = 0.003), heat-as-pain perception threshold visual analogue score 0.5 (r s = 0.279, p = 0.043) and deep-breathing heart rate variability (r s = −0.525, p < 0.001). Intra-epidermal nerve fibre density (fibres/mm) compared with age- and sex-matched control subjects (11.06 ± 0.82) was non-significantly reduced (7.37 ± 0.93) in diabetic patients with a normal Neuropad response and significantly reduced in patients with a patchy (5.01 ± 0.93) or absent (5.02 ± 0.77) response (p = 0.02). The sensitivity of an abnormal Neuropad response in detecting clinical neuropathy (neuropathy disability score ≥5) was 85% (negative predictive value 71%) and the specificity was 45% (positive predictive value 69%).


The Neuropad test may be a simple indicator for screening patients with diabetic neuropathy.