Is anyone aware of a modifier that can be used for a snf resident who visits a doctors office and has labs performed. I bill for an endocrinologist, the patient went to drs office for consult and they performed lab tests at the office. Medicare paid at first, but is now requesting refund. They state that these services should be paid by SNF (they allowed consult). I'm thinking I'm missing a modifier that would allow payment. I'd appreciate any help.