Designing, fabrication and evaluation of a rapid, point-of-care and noninvasive system for the detection of lead (Pb).

Non-invasive collection of biological sample such as sweat, urine, saliva, hairs and, stool and onsite detection of anlaytes in those samples is an interesting and viable approach for rapid screening of various toxicants in body. Environmental exposure/presence of lead (Pb) and its rapid detection provide one such opportunity. A chemical spot based colorimetric method and a transdermal patch device based on this spot test, is developed for rapid and qualitative assessment of inorganic lead (Pb) in non-coloured biological or environmental liquid samples. The transdermal patch system contains two important parts, a chemical spot prepared on a thin glass sheet and, an absorbent paper (11 µm pore size). A one step colour development reaction is able to identify the presence or absence of Pb. In-vitro evaluation for sensitivity and cut-off value determination, within run and between run precision testing, specificity testing were done. In-vivo evaluation of the developed patch system was performed in occupationally lead-exposed subjects and in control volunteers. In-vivo field testing results were further validated with gold standard test for lead detection. Blood lead levels and patch lead levels were found to be positively correlated (r = 0.57, P < 0.0001). In addition, the sensitivity and specificity of device in identification of Pb was found to be 75.93% (95% CI = 62.36%-86.51%) and 95.24% (95% CI = 76.18%-99.88%). The developed system appears as a reliable, non-invasive rapid test with minimum step involve for identification of Pb in a given system.