The Brits are working on an app for your cell phone that can detect bacterial infections. They're starting out setting it up for STD's but if you can detect one sort of infection, you should be able to test for many others.
Just lick the touch pad, and if it's really Dengue fever, the phone automatically calls an ambulance. Or if it's something more interesting, it calls a haz-mat team and notifies the morgue.
Next up, obviously, will be genetic screening. You lick the touch pad, and your info is stored. Someone else licks the touch pad, and you know right away if you really should be making those child-support payments, or if you're too closely related to be dating. This could be especially helpful in places like rural Arkansas.
The possibilities boggle the mind.