It would seem to me that if a doctor had a legitimate reason to be asking those questions, he would need to conduct real medical tests for the information he actually needs.
If for example you are at risk of having hepatitis and if that would be a problem with the medication for another condition (as some popular commercial keeps saying it does) then regardless of your answer to a question designed to determine your risk of exposure to hepatitis, the doctor had better be testing your blood to see if you have or have not been exposed.
This sounds like a bid for statistical data and actuarial data. If indeed we are headed for a Single Payer system then both kinds of data would only be useful to long term budgeting and strategies. In the absence of a commitment to Single Payer then to solicit and record such data is simply a gaping opportunity for abuse.