There's a great write up at Canada.com about Confirm BioSciences product, HairConfirm. The one-time use kits make it easy to detect drug use in people of all ages, but it is especially beneficial to parents of teens.

Parents can use the tests on their kids by collecting a small sample of hair-about 30-40 strands. This can then tell you if your kid has merely tried drugs, or if they are flat out addicted.

Drug testing such as this can really discourage drug use in teens. However, you shouldn-t use this test without your teen's knowledge. You might find out what you want to know, but is that worth the loss of trust? Just something to think about.