GP and CQ: The Therapy Modifiers on RTM Claims

For physicians, RTM claims are relatively modifier-light. For physical therapists, two therapy modifiers enter the picture — GP and CQ — and getting them right is part of billing RTM cleanly under a plan of care. Neither is complicated once you see what each one is actually saying.

GP — furnished under a PT plan of care

The GP modifier signals that a service was furnished under a physical-therapy plan of care. When a PT bills RTM, the therapy lines carry GP — it's how the claim communicates that this is therapy delivered under a PT plan. It's the baseline therapy modifier, and for PT-billed RTM it's expected on the relevant lines. (The plan-of-care foundation is covered in RTM for physical therapists.)

CQ — when a PTA furnishes part of the service

The CQ modifier comes into play when a physical therapist assistant furnishes a meaningful portion of the service. It identifies PTA involvement and is associated with the therapy-assistant payment differential. CQ doesn't replace GP — it rides alongside it. And it only ever appears on a therapy line; you won't see CQ on a physician's claim.

GP says “under a PT plan.” CQ says “a PTA did a meaningful share.” On a PT claim they travel together.

The de minimis standard

What's “meaningful”? CMS uses a de minimis standard: CQ applies when a PTA furnishes more than 10% of the service (strictly greater than 10%, not 10% or more). At or below that threshold, the involvement is de minimis and CQ isn't required. Because RTM management isn't a tidy per-minute split, many practices capture this as a provider attestation — the supervising PT answers the “was more than 10% furnished by the PTA?” question directly.

Getting the modifiers right

The practical rule: PT-billed RTM therapy lines carry GP; add CQ when a PTA crossed the de minimis line; never attach either to a non-therapy claim. BoneArc applies the therapy modifiers based on the provider's discipline and the PTA-involvement attestation, so the right modifiers land on the right lines without manual tagging. As always, confirm modifier application with your biller and payer.