11.4 G-Codes, Ambulance, Pass-Through Devices, and 2026 Skin Substitutes

11.4 G-Codes, Ambulance, Pass-Through Devices, and 2026 Skin Substitutes

Quick Answer: G0463 is still the CY 2026 Medicare HOPD clinic-visit code. Ambulance HCPCS codes generally pay under the ambulance fee schedule (status indicator A), each line carrying a two-character origin/destination modifier. Device pass-through is status indicator H for 2–3 years; keep reporting C-codes after it ends. CY 2026 unpackaged sheet-form skin substitutes into APCs 6000–6002 with new status indicator S1 at $127.14 per cm².

Independent OpenExamPrep teaching for COC candidates groups these topics because AAPC's HCPCS domain explicitly includes professional services for Medicare patients, and because 2026 OPPS changed how hospitals pay for grafts and still pays ambulance somewhere other than APCs.

G-codes: Medicare-specific services

G-codes are HCPCS Level II temporary codes CMS creates for professional or facility services when CPT does not meet a Medicare reporting need (quality measures, coverage-specific visits, or payment-policy substitutes). Many G-codes never appear on commercial claims. On a Medicare hospital outpatient claim, G-codes are ordinary HCPCS lines: they still need a revenue code, a diagnosis that supports medical necessity, and an Addendum B status indicator.

G0463 — hospital outpatient clinic visit for assessment and management of a patient — remains an active 2026 HCPCS code. Under OPPS it continues as the Medicare clinic visit replacement for CPT office/outpatient E/M codes in the HOPD. CMS assigns clinic visits to a visit APC with status indicator V (clinic or emergency department visit; separate APC payment). Do not report G0463 for an emergency department professional-style visit; ED facility E/M stays in CPT. Do not report G0463 in a physician office that is not a hospital department. Do not invent a 2026 deletion: the January 2026 OPPS update did not retire G0463.

Off-campus provider-based departments append PO (excepted) or PN (non-excepted) to the clinic-visit line. Site-neutral payment policies can reduce what Medicare pays for G0463 in excepted off-campus departments and pay non-excepted departments at a Physician Fee Schedule-equivalent rate. CY 2026 also expanded PFS-equivalent payment to drug administration APCs in excepted off-campus departments. Those are payment adjustments on correctly coded lines, not reasons to drop G0463.

Other G-codes the outpatient coder meets include Medicare preventive services, some care-management or quality-reporting codes, and—new for skin substitutes—G0681–G0684 for application of non-sheet-form products (discussed below). Radiation-therapy G6001–G6017 were deleted January 1, 2026 in favor of revised CPT radiation delivery codes; do not pull a retired radiation G-code from memory.

When both a CPT code and a G-code could describe a service, follow the payer. Medicare hospital clinic visits use G0463. A commercial payer may still require CPT 99202–99215. The COC exam's HCPCS domain is explicitly about professional services for Medicare patients, so G0463 is the expected hospital clinic answer on a Medicare stem.

Ambulance: origin, destination, and not OPPS

Ambulance services are HCPCS Level II A-codes in the A0425–A0436 range (ground and air transport and mileage). Examples:

OPPS status indicator A means the line is not paid under OPPS. Ambulance is the textbook example, along with many clinical lab tests, therapy services, and non-implantable prosthetics/orthotics. Hospital-based ambulance claims still need correct HCPCS, but the Pricer is the ambulance fee schedule, not an APC.

Each ambulance HCPCS line—transport and mileage—carries a two-character origin/destination modifier. The first character is origin; the second is destination. Common characters include H hospital, R residence, S scene of accident or acute event, P physician office, N skilled nursing facility, E residential/domiciliary/custodial facility, G hospital-based ESRD, J freestanding ESRD, D diagnostic or therapeutic site other than P or H when used as origin, I transfer site between ambulance modes, and X (destination only) for an intermediate stop at a physician office on the way to the hospital. A residence-to-hospital emergency trip uses RH on both A0427 and A0425.

Mileage is a separate line (A0425 for ground). Do not assume the transport code includes loaded mileage. CMS requires fractional mileage units where applicable. Supplies used on the trip are included in the transport charge, not billed as A4550 on the ambulance line.

Hospital outpatient surgery patients who arrive by ambulance still show the ambulance on the appropriate claim with SI A. The surgery APC does not swallow the ambulance fee-schedule line, and the ambulance line does not become SI T just because it shares a date with an operation.

Pass-through devices: status indicator H and C-codes

Section 1833(t)(6) of the Social Security Act lets CMS pay transitional pass-through for new device categories for at least 2 but not more than 3 years. OPPS status indicator H means a pass-through device category: separate cost-based pass-through payment, not subject to copayment. The Integrated Outpatient Code Editor reduces that payment by the device offset already built into the procedure APC so Medicare does not pay for the device twice.

January 2026 OPPS (MM14361) preliminarily approved new device category codes C1607 and C1608 for pass-through effective January 1, 2026. Pass-through for C1826, C1827, and C1747 expired December 31, 2025; those categories remain active codes but payment packages into the primary service. April 2026 instructions added another device category (C1743) via quarterly review. The exam will not require a memorized roster of every live H-code. It will require this logic:

1. Identify the device category C-code that describes what was implanted or inserted.
2. Look up current SI: H means pass-through is live; otherwise the device is usually packaged (N) or otherwise not separately paid as pass-through.
3. Still report the C-code after expiration. CMS states that despite expired pass-through, hospitals must report device-category C-codes when the devices are used with OPPS procedures.

C1713 (implantable anchor/screw for opposing bone-to-bone or soft tissue-to-bone) is the classic textbook C-code. Its pass-through period ended December 31, 2002. It is a reporting example, not a 2026 SI H example. Using C1713 to explain what a device C-code looks like is correct; calling it currently pass-through is not.

Devices with FDA breakthrough designation can use an alternative pass-through pathway that does not apply the usual substantial clinical improvement test, but they must still meet the other pass-through criteria. Offset amounts live in OPPS Addendum P. Pairing rules matter: some pass-through C-codes may be billed only with listed CPT procedure codes.

Comprehensive APCs (J1/J2) still generally package most services, but CMS carves out specified exceptions that include status indicators G and H (among others) and ambulance. A pass-through device does not disappear inside J1 simply because the procedure is comprehensive; look up the current exception list rather than packaging H by habit.

Skin substitutes in CY 2026: unpackaged sheet-form products

Through 2025, OPPS packaged many skin substitutes into application procedures and split products into high-cost and low-cost groups, with C-codes C5271–C5278 describing low-cost application. CY 2026 changed that policy.

CMS unpackaged skin substitute products from their application services and created three characteristic APCs:

For CY 2026 CMS uses a single payment rate of $127.14 per cm² for APCs 6000–6002. Assignment is by FDA regulatory category, not by the old high-cost/low-cost price split. CMS created status indicator S1 for sheet-form skin substitute products so they can be paid separately under OPPS. Products assigned to APCs 6000–6002 receive S1.

Unlisted product codes for FDA-authorized or cleared products that lack a specific code:

C5271–C5278 were deleted effective December 31, 2025. Sheet-form application remains CPT 15271–15278. CMS continues to package the CPT add-on application codes (15272, 15274, 15276, 15278) in the outpatient hospital setting.

Non-sheet products are not in the same separately payable S1 construct. CMS created G0681–G0684 for application of non-sheet-form PMA, 510(k), or 361 HCT/P products. Those application G-codes are status indicator N (packaged). Do not report CPT 15271–15278 for non-sheet application. G0681–G0684 are effective January 1, 2026 (implemented on the April 2026 update files).

July 2026 OPPS corrections moved sheet-form products A2032 and A2034 from incorrect status indicator N to S1, retroactive to January 1, 2026. That correction is a reminder to trust current Addendum B, not a printed memory of January assignments.

BLA skin substitutes remain payable as biologicals under the drug methodology. Non-BLA sheet-form products are incident-to supplies with separate OPPS payment via S1. JW/JZ discarded-drug billing does not apply to those non-BLA incident-to products; unused product is not billed with JW.

Integrated Medicare-patient scenario

A Medicare patient is seen in an on-campus hospital clinic (G0463, no PO/PN) for a chronic wound. The physician applies a sheet-form 510(k) skin substitute. The coder reports G0463 for the clinic visit, the specific Q- or A-code (or Q4432 if unlisted 510(k)) for the product with SI S1, and CPT 15271–15278 for sheet application as documented, remembering add-on application codes package. If the same patient had arrived by ambulance from home, A0429 or A0427 plus A0425 would appear with modifier RH, SI A, outside the clinic APC. If an implantable anchor is later placed in SDS, C1713 (or the current category) is reported even though it is not SI H.

Common traps

Do not use G0463 for ED visits or for commercial clinic visits that require CPT E/M. Do not treat ambulance as SI T packaging. Do not call C1713 a current pass-through device. Do not bill deleted C5271–C5278 in 2026. Do not put SI S1 on non-sheet G0681–G0684 application codes. Do not apply JW to 2026 non-BLA skin-substitute waste.