| Modifier | Description |
|---|---|
| N1 | Group 1 oxygen coverage criteria met |
| N2 | Group 2 oxygen coverage criteria met |
| N3 | Group 3 oxygen coverage criteria met |
| NB | Nebulizer system, any type, fda-cleared for use with specific drug |
| NR | New when rented (use the ‘nr’ modifier when dme which was new at the time of rental is subsequently purchased) |
| NU | New equipment |