Health insurers are sending out letters, news articles are publishing the ease with which you can keep your personal health record. Why are you doing this?
You are giving information out that most doctors will not rely on (as is in the fine print of your agreement, LOOK and READ). That means that even if you say you have or don't have something, you will NOT prevent duplicate testing, exams and bills.
That's why these things are being sold to consumers (Oh, I know, they're free...you can freely compromise your own privacy) as a handy means of gathering information in one spot.
Better spent time would be on keeping track of your insurance premiums and bills. First of all, you may uncover some real fraud (non occurring testing, rebilling, double dipping), second, your insurance claims forms and physician bills include what has been done, and third, when you are battling your insurer they care much more about money than health...cynical or true, up to you.
In keeping your personal billing record...instead of your personal health record, you have benefits that are not included in this new data mining approach by insurers: First, you can follow the money, second, you can track dates and codes of what procedures health services providers are collecting money for, third, you can actively address how your information is being used by subcontracted third parties: If you have diabetes and you get a call from a third party contractor looking to manage you, check out how that little leap over privacy was done, lots of times it's opted into by you!
If you still feel important by filling these things out, look into the new cases of identity theft based on medical records...this probably won't become an issue until people are denied health insurance coverage for phony conditions claimed by those seeking money off your medical id. If you are unafraid, also consider how hard physicians RESIST any sort of uniform reporting of what they're doing, always couching their arguments in terms of patient privacy.
These new "tools" are a sham distraction for consumers and if you have one thing you want doctors to know, get a medic alert bracelet instead.