Studies have shown that up to 30% of decaf coffees ordered at coffee houses and restaurants contain unacceptably high levels of caffeine, or are not decaf at all. Here's, you could lug around someone that is highly allergic to the stuff and make them try everything before you drink it. However, that course of action probably isn’t the best way to learn the truth. What you should do instead is pick up a pack of these Caffeine Test Strips. These little suckers can tell you just how much caffeine your beverage contains. You just dip one into the beverage (you’ll need to separate some out from your cup, as contact with the strip can contaminate the liquid) and wait for about 30 seconds for a resultThe strips come in packs of 20, and cost around $10. via [techfresh]