What is a GC modifier?

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Modifier GC means that a medical service was performed in part by a resident under the direction of a teaching physician, according to the Noridian GC Modifier Guide.

When to Use Modifier GC

  • Teaching facilities: Submit this code when a resident or fellow helps provide care in a teaching hospital or clinic.
  • Any service type: Use it for evaluation and management (E/M) visits, surgeries, and anesthesia.
  • Physician presence: The teaching physician must be present for the key or critical parts of the service and stay available during the rest of the procedure.

Documentation Rules

  • Shared notes: The medical record must show that both the resident and the teaching physician took part in the care.
  • Key participation: The teaching physician must document or confirm their physical presence during the critical portions of the service.
  • Signatures: Both providers should have clear, dated signatures in the patient chart.

Is GC a valid modifier?

Yes, GC is a valid HCPCS Level II modifier in medical billing and coding.

What Modifier GC Means

  • Definition: It indicates that a service was performed in part by a resident under the direction and supervision of a teaching physician.
  • Usage: Appended to CPT or HCPCS codes (such as E/M services, surgeries, or anesthesia) when a resident or fellow participates in patient care under Medicare teaching rules.
  • Requirements: The teaching physician must be present for key or critical portions of the service and document their involvement.

You can read more details about the rules and compliance guidelines at the AAPC Coding Newsletters.

Is modifier GC only for Medicare?

No, the GC modifier is not strictly limited to Medicare, though it originates from Medicare guidelines and is primarily required by federal and state government payers.

Who Requires the GC Modifier?

  • Medicare and Medicaid: These programs explicitly require the Modifier GC to show that a resident performed part of a service under a teaching physician's supervision.
  • Other Government/State Payers: Some state Medicaid or managed Medicaid programs adopt Medicare's teaching physician rules and also require the GC modifier.
  • Commercial Payers: Most private or commercial insurance companies do not recognize or require the GC modifier. Many commercial plans prefer to be billed under the attending/teaching physician's NPI as if the physician performed the entire service directly, without indicating resident involvement.

Best Practices for Non-Medicare Payers

  • Always check the specific payer contract or billing manual.
  • If a commercial plan has no official policy regarding teaching physician modifiers, adding the GC modifier can sometimes cause claim rejections or processing delays.

When to give a GC modifier?

Use Modifier GC when a service is performed in part by a resident physician under the direct supervision and direction of a teaching physician.

When to Use Modifier GC

  • Teaching Settings: Append to claims when a resident participates in patient care in a teaching hospital or approved facility.
  • Key/Critical Presence: The teaching physician must be physically present during the key or critical portions of the service or procedure.
  • Broad Range of Services: Use for Evaluation and Management (E/M) visits, surgical procedures, and anesthesia services.
  • Documentation Support: The medical record must show that both the resident and the teaching physician were involved, with a signed attestation from the teaching physician.

When NOT to Use Modifier GC

  • Do not use if the teaching physician was not involved or not present during critical parts of the service.
  • Do not use for services performed by medical students (Medicare does not cover student services).
  • Do not use if qualifying for the Primary Care Exception, which instead requires Modifier GE.

Does modifier GC reduce payment?

No, modifier GC does not reduce payment for a medical service.

When the rules for the GC Modifier in Medical Billing are met, Medicare and other participating payers reimburse the service at the exact same rate as if the teaching physician had performed it completely on their own.

Key Details About Modifier GC

  • Purpose: It shows that a service was performed in part by a resident under the direction and supervision of a teaching physician.
  • Payment Rate: 100% of the standard allowable fee (no discounted or reduced rate is applied).
  • Requirements: The teaching physician must be physically present during the key and critical portions of the service.

Difference between GC and GE modifier in Tamil

9 related questions found

What is the GC modifier?

Modifier GC is a medical billing code that shows a service was performed in part by a medical resident under the direction and supervision of a teaching physician.

You can review specific billing definitions and rules on the Novitas Solutions Medicare Portal or read more details via AAPC General Coding.

When to Use Modifier GC

  • Teaching Settings: Used when billing Medicare, Medicaid, or other federal payers for care in a teaching hospital or facility.
  • Shared Services: Applied when a resident takes a patient history or does an exam, and the teaching physician reviews and completes the visit.
  • Procedures: Used during surgeries or anesthesia when the teaching doctor is present for the key parts of the care.

Rules for the Teaching Physician

  • Presence: The main doctor must be there during the critical or key portions of the service.
  • Availability: The main doctor must be immediately available during the rest of the procedure.
  • Documentation: Notes must show that both the resident and the teaching doctor took part in the care.

Does modifier 25 or GC go first?

Modifier 25 goes before modifier GC when both are required on an Evaluation and Management (E/M) service code.

Rules for Modifier Sequencing

  • Payment/Pricing Modifiers First: Modifier 25 is a payment/pricing modifier because it affects reimbursement directly by unlocking separate payment for an E/M service billed on the same day as a procedure. Payment modifiers always take the first position (primary slot) on the claim line.
  • Informational/Program-Specific Modifiers Second: Modifier GC is an informational or statistical program-specific modifier used to indicate a service performed by a resident under the direction of a teaching physician. Informational modifiers are always placed after payment modifiers.

Why is the cg modifier used?

The CG modifier is primarily used by Rural Health Clinics (RHCs) on Medicare claims to identify the primary, medically necessary service or qualifying visit of the day.

How the CG Modifier Works in RHCs

  • Designates the Primary Reason: It is appended to a single medical or mental health HCPCS/CPT code that represents the main reason for the face-to-face visit.
  • Bundles Charges: The line with the CG modifier holds the bundled charges for all services provided during the visit that are subject to coinsurance and deductibles.
  • Triggers Payment: It tells the Centers for Medicare & Medicaid Services (CMS) which line item qualifies for the All-Inclusive Rate (AIR) payment.
  • Preventive Services: If a patient only receives preventive services, the CG modifier goes on the primary preventive HCPCS code instead. If both preventive and medical services occur on the same day, it is attached only to the primary medical service.

(Note: In some separate Durable Medical Equipment [DME] contexts, a CG modifier is also used to designate specific non-elastic or rigid spinal garments, but its most widespread medical billing use is for RHC encounters).

Does the GC modifier go on procedures?

Yes, you should append the GC Modifier to procedural codes, including surgical and testing procedures, when a resident performs part of the service under the direction of a teaching physician.

Key Rules for Procedural Use

  • Definition: The GC Modifier means "this service has been performed in part by a resident under the direction of a teaching physician".
  • Applicability: It applies beyond Evaluation and Management (E/M) visits to surgical procedures, diagnostic tests, and pathology services.
  • Physician Presence: The teaching physician must be present for the key or critical portions of the procedure.
  • Multiple Modifiers: You can combine it with other required procedural modifiers, such as professional component modifiers (e.g., modifier 26).

Can a GC modifier be used for a fellow?

Yes, you use a GC modifier for a fellow when they are enrolled in an accredited graduate medical education program and working under the supervision of a teaching physician.

When to Use the GC Modifier

  • Trainee status: Medicare and other federal payers define a "resident" to include any intern, resident, or fellow in an approved training program.
  • Teaching supervision: Append the GC Modifier when the fellow performs part of a service under the direct direction of a teaching physician who is present for key or critical portions.
  • Applicable codes: Use it on evaluation and management (E/M) visits, surgical procedures, and testing.

Exceptions

  • Fully licensed/independent practice: If the fellow is fully licensed, not in an accredited training program, and acting as an independent employee credentialed by the practice, their services may be billed under their own NPI rather than through a teaching physician.