The 90 modifier is to be used when the billing laboratory refers a specimen to another lab for testing. In these cases, the billing lab is titled the “referring lab” while the lab that actually performed the test is the “reference lab.”
Information | Loop | Field | Identifier |
---|---|---|---|
Billing lab’s CLIA number | 2300 | REF02 | X4 |
Reference lab’s CLIA number | 2400 | REF02 | F4 |