Check out this article about PharmChek drug testing patches:

Chem Lab: Fun Facts about Sweat-Absorbing Drug Test Patches and Marijuana | Wired Science from Wired.com

Have any of you ever worn one of these patches?
Do you agree that this is a bigger invasion of privacy than pee testing?

I think it is funny that the instructions say to wear it on your chest, but the official website shows it on a shoulder.