referral

(noun) a person whose case has been referred to a specialist or professional group. Example: "The patient is a referral from dr. bones."

(noun) a recommendation to consult the (professional) person or group to whom one has been referred. Example: "The insurance company says that you need a written referral from your physician before seeing a specialist."

(noun) the act of referring (as forwarding an applicant for employment or referring a matter to an appropriate agency).