According to New Scientist (Jan. 28 to Feb. 3, 2006), a South African inventor has developed a watch that automatically sticks you every six hours (with an 0.5mm needle that emerges from the watch's underside) and searches the resulting blood sample for the malaria parasite. Its alarm goes off when the search is successful.
Except for the part about the needle, this technology sounds pretty attractive. Unobtrusive, lightweight, only marginally invasive. And it's certainly easy to imagine where it's going: higher sampling rates and detection of a wide range of bacteria, viruses, sugars, cholesterols, fats, hormones, vitamins, fatigue poisons, and so on. At the limit, you'll be carrying a complete hematology lab around on your wrist (my sympathy to complete hematology lab workers everywhere), and its wireless connectivity will hook it up to your doctor's or hospital's or, perhaps, insurer's servers.
Granted, at first blush, the idea of giving your insurance company access to your real-time blood workups seems hopelessly loopy--whatever they learn is unlikely to be good for your premiums. But maybe, in a twisted sort of way, it makes sense. Suppose we toss in GPS (to guide any ambulance that might be trying to find you) and heart rate monitoring. Suppose further that you're given a base premium to which (from which) incremental amounts can be added (subtracted) based on your behavior. So if you go running in the morning, there'll be an e-mail from your insurance company that reads, "Good run! We're going to knock $5 off your premium this month." And then, alas, it's lunch time...and you have the bratwurst. When you get back to your desk, there's an e-mail that says, "We dunno what on earth that was...but it's going to cost you $25."
The point here is that the insurance company could actually become an active (even aggressive) participant in your health care, rather than the passive observer it is today. I've pitched this idea to a number of people and many of them (mostly the less physically fit ones, like me) are actually fairly receptive to it--they like the motivation and discipline that a carrot/stick relationship with their insurer would provide. It's a brilliant concept and I fully intend to sign up once it's available...right after you do.