CPT® 76882 and 31 pos

I have been getting rejections for CPT® 76882 with a pos 31 stating that co5/procedure inconstitant with place of service. (Medicare is primary) I am a IDTF that frequents nursing homes and have not had an issue in the past with paid claims. When I spoke with someone at Medicare, she stated that RAD 841 would explain it to me. I read RAD 841 and it did not. Any help on this would be so apprciated!!
Thank you
Missy