It's a third-party service hired by medical practices to confirm upcoming appointments. They call, remind you of your appointment and get confirmation you are still coming (assuming they call the right person, of course). Mine was for an IPL laser treatment I have scheduled in the coming week at Mid Atlantic Skin Institute.
Note: It's a nice reminder. But just a warning: they did call two times in the span of 1 minute and a half before noon; proceeded to leave a voicemail after the second try. Then called me just now and I finally picked up and confirmed everything so they would stop calling. They are kind of persistent to the point of harassment.
Didn't recognize the number so didn't answer. But yes, it was an appointment reminder for my appointment tomorrow with Shah associates (Calvert County MD). She did leave a detailed message on the voice mail, and I only received the single call.