There is a company just being formed that is trying to put, in a safe and secure database, a persons complete medical history with all scans etc. included. You would have a coded password for any doctor to access all this over the web that you could then give out. I have looked at the Beta version, and it is very complete and can be expanded into more things personal, such as living wills, family contact information, and more.

My dog has a small grain of rice size computer chip in his shoulder. If he ends up at the pound or at a vets office they have a scanner that they pass over his body that reads the tiny chip, and that has a code number it gives out. The vet or pound then can call a toll free number and access all the information about his owners phone number and medical records. It is infinitely updatable over the web by me. I personally would be wiling to have something like this put in me, but it would never be allowed. Fear of big brother and all that. So hence my 3X5 laminated card.

I don't think the medic alert bracelets that are premade would have enough information, unless they gave a first responder or doctor a mechanism for obtaining the massive amount medical data we all have, such as via the new company mentioned above.

Also related to lisa's post, don't think those three year old or 5 year old scans and test results are without value. They offer baseline data to track trends or to distinguish something new from something pre-existing but perhaps not mentioned in a previous report. For instance in my case the radiologist has stopped commenting on the small black spot on my liver for the last three years which has remained unchanged. Without the first one where it appeared, someone reading the last one might think it was something new.