So I got an account with 19 units of 88341. I went to the MUE and allowing 9 to be billed and others are needing a modifier. I am not sure which modifier to use. I think it would be -91 because it was the same lab testing on multiple units. Payer is Medicare; they will allow 9 of them but the other 10 need modifier or we have to adjust them off. Any help would be appreciated.