Copied from wiki: In the context of a relational database, a row—also called a record or tuple—represents a single, implicitly structured data item in a table. In simple terms, a database table can be thought of as consisting of rows and columns or fields.[1] Each row in a table represents a set of related data, and every row in the table has the same structure.
So Datensatz (row, singular of Datensätze) isnt a medical term, but a term for information technology. But there really isnt a good sounding German translation for it. Maybe "Patientenberichte" (patient reports)?
A Patientenbericht would be more like an essay on a specific case, I think. I don't think that fits with the author's idea, although it'd probably fit the story quite nicely ^^;
Medizinischer Datensatz is perfectly fine, technically, but like I said, in the context of medicine, even if it's not an actual paper folder, it's usually just called Krankenakte or Patientenakte (the official term for what's used in Germany is "Elektronische FallAkte" (EFA, electronic case file), but as you can imagine, nobody actually says that). It's like, say, police work and calling something a "case file" even if it nowadays might mean a digital database entry and not an actual paper file.
(also, -satz here is meant in the same way as "set (of objects)" so it's not necessarily just a row or column; it can be complex as whatever. It just implies some logical relation between the various entries. "Datensätze" (datasets) are then saved in "Datenbanken" (databases). So the Dynasty database might contain a dataset of users and passwords, and one for mangas and their authors and ... it's the same structure in German as in English. In this case it obviously implies the logical relation is everything that's got to do with the patient's medical history; previous check-up results and a history of illnesses and operations and whatnot)
... I kinda forgot what my point was. Well, basically I'm saying a German author probably would have worded the subtitle differently even if this one isn't strictly wrong (except for the der/des thing). Still, it's a pretty good effort - I just yesterday read some werebear thing on Kindle that had the werebear speak some German and it was just ... urk. ^^