This has seemed a good idea to me, and certainly one which an evolved system for a health service should have the capacity to do.
Having spoken about it at a meeting, I then jotted down a rough diagram of how it could be done. http://www.flickr.com/photos/midgley/3622837633/ There are a family of ways of course, and a more distributed one, not depending on aggregation in the same central place for all patients would be better, and fit countries other than the UK better. But I submit this as the first drawing of a proof of concept -- Adrian Midgley Exeter, UK
