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


METHODS
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.


RESULTS
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 >or=5) was 85% (negative predictive value 71%) and the specificity was 45% (positive predictive value 69%).


CONCLUSIONS
The Neuropad test may be a simple indicator for screening patients with diabetic neuropathy.
Quattrini
C
C
Division of Cardiovascular Medicine, Core Technology Facility, University of Manchester, 46 Grafton Street, Manchester M13 9NT, UK.
Jeziorska
M
M
Tavakoli
M
M
Begum
P
P
Boulton
A J M
AJ
Malik
R A
RA
D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D009460:Neurologic Examination / Q000295:instrumentation* / Q000379:methods; D012016:Reference Values; D014034:Toes / Q000294:innervation / Q000503:physiopathology