A glucometer is a device used to test milligrams of
glucose per deciliter in
whole blood. They're really handy if you're
diabetic, like me. The most popular glucometers are the OneTouch series by
Lifescan. Throughout the history of the glucometer, Lifescan has produced some of the most user-friendly machines. When I was a kid, I had a
OneTouch II, which was much better than the other kinds, because it only took 45 seconds, and it was a fairly small machine. Then, when I was about 16 or so, I got a
OneTouch Profile which was full of neat features like 14 and 30 day averaging and
insulin records for those folks on sliding scales. This, too, took 45 seconds, but it was a somewhat larger machine, and did not take the abuse nearly as well. When it broke, I went back to the old one. Recently,
plasma-calibration technology has become cheap and small enough to enable Lifescan to produce the
OneTouch Ultra, a fabulously small machine that gives results in only 5 seconds.
Older model glucometers tend to test blood sugar through the reflection method, which means that when blood is applied to a small circle (or square, in the case of some very old, non-Lifescan meters) the test strip, the reagents in the paper change color, and when a laser is reflected off the circle, the machine judges how much glucose is in the blood by how much light comes back.