Provider's Primary Specialty

I just had a claim sent back to me saying that I need to resubmit with the "Provider's Primary Specialty". I called United Health Care about this and the lady I spoke to had no idea what that was about, because this was before the claim had officially gotten into there system she was unable to look at the claim to see the problem. She said that someone would contact me within 15 business days.

Is there somewhere on the CMS-1500 that this is supposed to go? I have submitted several claims to them before with no incident.

Thanks,

Nick

Provider's Primary Specialty