[baylisscg]

No, it's not centrally collected. There is a national eHealth system, MyHealthRecord, but it's opt in for patients, supplementary to your provider's records, and various pieces of privacy legislation at the state and national level make handing out this data, at best, legally fraught.

Speaking from experience. Getting data out of a hospital is phenomenally hard even when the hospital is wants to provide it. Patient confidentiality is a thing they all take very seriously.