Modifier CQ. Service furnished in whole or part by a physical therapist assistant (PTA) — triggers 85% of the PT rate; required when a PTA furnishes more than 10% of a service (since 1/1/2020, alongside GP).
Reference only — CPT descriptors are AMA-copyrighted (paraphrased). Payment percentages and acceptance vary by payer; verify against the current CPT/HCPCS files and payer policy.