In simple words: This means the service was done in a Veterans Affairs hospital by a doctor in training under supervision.

Modifier GR denotes services rendered in a VA facility by a resident provider, a medical graduate working under the supervision of an attending provider. The VA facility appends modifier GR to the appropriate HCPCS code for the service and submits the claim under the name of the attending provider. This modifier has the same consequences as modifiers GC and GE, but is used specifically for VA claims.

Example 1: A resident performs a routine check-up on a veteran patient in a VA clinic under the supervision of an attending physician. The modifier GR is appended to the appropriate HCPCS code., A resident assists in surgery performed by an attending surgeon at a VA hospital. Modifier GR is appended to the surgical procedure code., A resident provides follow-up care to a veteran patient after a procedure, under the guidance of an attending physician, in a VA medical center. The appropriate HCPCS code for the follow-up care is appended with modifier GR.

Documentation should clearly identify the attending provider and the resident provider involved in the service, along with details about the level of supervision provided.