Wearable patch for the electrical, durometry and optical skin measurements in tuberculin skin test

Early diagnosis and prompt treatment of latent tuberculosis infection is important to reduce mortality and morbidity especially among patents with immunocompromised conditions. The tuberculin skin test is a routine screening test for latent tuberculosis based on intradermal immune response sensitization. Results depend on the induration size and risk factors of subject. This test, however, suffers from uncertainty and non-specificity due to ambiguous cutoff value and intra-observer variations. We propose to develop a bandage-type flexible patch to monitor skin impedance, temperature, tissue oxygen saturation, and induration diameter after the tuberculin administration. The multi polymeric patch will consist of highly fibrillated microstructured plastic pillars to mimic the microscopic setae hair at the bottom of gecko feet, allowing dry operation and minimal motion artifact. This flexible device is to be adhered to the injection site recording relevant physiological changes manifested as a result of the immune response towards the injected tuberculin in order to aid the disease assignment. The proposed device not only provides an objective measurement for the tuberculin skin test, but also supplies non-invasive electrodermal readings to supplement the diagnosis of latent tuberculosis infection and epidemiological studies.