Has anyone had to bill 87798 with multiple units to First Coast / Medicare Mac, for a clinical laboratory, POS 81.

When billing to the Palmeto / Medicare Mac, you can put up to 13 units on one line, with no modifier, and all units pay.

First Coast rejects the claim, stating there are billing submission errors. We have tried using modifier 91 and 59, but they only pay for one unit and deny the rest as a duplicate.

Any insight would be greatly appreciated.

Thank you.