The authority said it took steps after discovering the tax number, 121212-1212, was used by hospitals and clinics to teach healthcare staff how to work different databases, the Swedish news agency TT reported Wednesday.
The agency said it feared a newborn might end up with the number -- which is created from the birth date, 12/12/12, and four additional numbers -- and be confused with fictional patient Tolvan Tolvansson, a name made from "tolv," the Swedish word for "twelve."
"If we hadn't blocked it, a newborn could have ended up with a load of incorrect health information tied to their ID number," Tax Agency spokesperson Ingegerd Widell said.
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