What are the concerns with medical records on the block chain and Protected health information?
hashes are stored being a reference to a record, the actual record itself will not be stored on the blockchain
I think this is a pretty succinct description of how blockchains would be used with information that is governed by privacy and other laws. The interesting part of the technology has nothing to do with what info goes into the Blockchain (existing laws and regulations will be followed) but with how it changes interaction due to change of info control and disintermediation. In healthcare for example, one often hears of patient/Doctor relationship, which isn't just that today in ANY health system on Earth... With blockchains we have the tech to make it patient <-> Doctor relationship to the fullest. Whether the tech gets adopted fully in healthcare setting is what we shall see.