I am in the process of translating a short brochure for my office into Spanish and I'm having some issues with the translation of the word "referral". I'm originally from Puerto Rico and over there, I've always used and heard the word referido as a direct translation for this term. However, because it sounds like such a calque, I verified this word in the DRAE dictionary and it doesn't appear. I'm not sure if it would actually be understood by a more general target Hispanic audience. (For the record, many of our clients tend to be South American, but really, I have no idea who's going to be reading this.) I have been unable to find any other satisfactory solutions, though. A main problem is that the brochure format has already been designed and there's a limited amount of space to fit the phrase into, so, although it doesn't necessarily have to be a single word, it does need to be something relatively concise. (Yes, I am aware that Spanish tends to be longer than English by nature.)
I also found derivar and remitir/enviar for "refer", but none of these seem to work in noun form. How do other native speakers express this concept in their respective countries? Should I just turn it into a verb?
For context, I'll add that it's about a collaboration between a legal office and a medical center. The brochure is stating that the legal office can only see people who are referred to them by their healthcare provider. The phrase in question is "Appointments by referral only".
Any help would be much appreciated.