Handy to know, from what is written, these patches are pretty prevalent nowadays... What the paper says is that the Courts are aware of the problems (or at least the UPPER COURTS are) with such patches and the ability of environmental drugs - ie. smoke, or airborne matter, to bind to skin in such a way as to show a 'false positive'... Kind of useful, as it provides a real way around the problem.

It is a patch - they use it as an ongoing "drug test" - the patch absorbs the drugs that are given off in sweat... Trouble is that the skin also absorbs drugs, which may be in the environment of the person wearing the patch, through no fault of their own.