I am not sure if a state subpoena can even apply across state lines. Time to send up the Bat Signal for albaby.

Ah, old chum - the Albaby-Signal has been lit! To the message boards!

The short answer is that state power stops at the state line. The slightly longer answer is that there are a **ton** of interstate compacts to facilitate the civil and criminal justice systems in order to work around that fact.

The states agree to share all kinds of information, records, access, and a host of other things to make sure that stuff runs smoothly when parties are in different jurisdictions. So, for example, there's the Uniform Interstate Depositions and Discovery Act - a model statute that most states have adopted to provide interstate cooperation among courts for handling those types of things. So if plaintiff X in Texas needs to subpoena records from defendant Y in Georgia, there's a Georgia statute on the books that directs how their state courts should (or should not) accommodate that request from their sister Texas courts, exercising their own state power.

There are agreements on all kinds of government stuff: sharing driver's license information, criminal records, licensing documents, and the like. It wouldn't shock me if there was some type of interstate compact dealing with medical records, so that if law enforcement in one state might have the same ability to request medical records in another state that the local cops there could do. But this is an unusual enough type of request that it might not fall neatly within that framework.