CPT G0438 Medicare Reimbursement Rate in California (2026)

HCPCS Level II code G0438 represents annual wellness visit, initial. Annual wellness visit; includes a personalized prevention plan of service (PPS), initial visit.

As a G-code, G0438 is a Medicare-specific HCPCS Level II code created by CMS for services and procedures that don't have a CPT equivalent. Payment follows the standard CMS Physician Fee Schedule methodology, calculated from the code's Relative Value Units (RVUs) adjusted for the Geographic Practice Cost Index (GPCI) of the billing locality.

For 2026, Medicare's allowed amount for HCPCS G0438 in California is $156.52 when the service is provided in a non-facility setting and $116.25 when provided in a facility setting. These figures are calculated using locality 0500000 (California (Rest of State)), with a Work GPCI of 1.040, Practice Expense GPCI of 1.142, and Malpractice GPCI of 0.661, multiplied against the 2026 conversion factor of 32.3465.

California's non-facility allowed amount for G0438 runs roughly 6.8% above the national reference rate of $146.53. The variance is driven primarily by California's GPCI multipliers, which reflect cost-of-practice differences relative to a national baseline of 1.000.

Beneficiaries in Original Medicare typically owe 20% of the allowed amount as coinsurance after meeting the Part B deductible, unless the cost-sharing is covered by a Medicare Supplement (Medigap) policy or absorbed by a Medicare Advantage plan with different cost-sharing rules.

The $40.27 gap between the non-facility ($156.52) and facility ($116.25) allowed amounts comes from the Practice Expense (PE) RVU. When a service is performed in a facility — a hospital outpatient department, ASC, or inpatient setting — the facility itself bills for and is reimbursed for the overhead, equipment, and clinical staff. The physician's PE RVU is therefore reduced.

When the same service is rendered in a non-facility setting (a physician's office, freestanding clinic, or the patient's home), the billing provider absorbs the full overhead, so CMS pays the higher PE RVU. For HCPCS G0438, the non-facility PE RVU is 1.92 versus a facility PE RVU of 0.83.

Place-of-service reporting on the CMS-1500 claim must match where the service was actually delivered. Misreporting POS to claim the higher non-facility rate is a documented OIG audit target.

Medicare's Physician Fee Schedule formula multiplies each RVU component by its corresponding GPCI, sums the three, then multiplies by the conversion factor. For HCPCS G0438 in California, the math works out as: (Work RVU 2.43 × Work GPCI 1.040) + (Non-Facility PE RVU 1.92 × PE GPCI 1.142) + (MP RVU 0.18 × MP GPCI 0.661) × Conversion Factor 32.3465 = $156.52.

The Work component pays for the physician's time, intensity, and skill. The Practice Expense component covers the office overhead, supplies, and clinical staff. The Malpractice component covers professional liability. CMS recalibrates the RVU values annually as part of the Final Rule.

G0438 is commonly billed with the following modifiers: 25. Modifier 25: significant, separately identifiable E&M service on the same day as a procedure.

Modifier choice can change Medicare's payment, override an NCCI edit, or force a separate line of payment. Always document the clinical justification for any modifier in the medical record before submission.

HCPCS G0438 carries a global surgery indicator of XXX — global concept does not apply. The global period determines which related pre-operative and post-operative services are bundled into the single allowed amount and cannot be billed separately.

Because the global concept does not apply to G0438, related E&M services on the same day are generally separately billable when documented and medically necessary.

If you're researching G0438, these related HCPCS Level II codes are commonly looked up at the same time:

G0008 (administration of influenza virus vaccine); G0009 (administration of pneumococcal vaccine); G0010 (administration of hepatitis b vaccine); G0439 (annual wellness visit, subsequent); G0444 (annual depression screening, 15 min); G0463 (hospital outpatient clinic visit).

• G0438
• G0008
• G0009
• G0010
• G0439
• G0444
• G0463

California providers submitting claims for G0438 should bill their Medicare Administrative Contractor (MAC) using locality 0500000. If your practice spans multiple ZIP codes inside California, the locality may differ — CMS publishes a ZIP-code-to-locality crosswalk (LOCCO file) that resolves the correct locality and PEs accordingly.

Allowed amounts shown here are Medicare reference values from the 2026 Physician Fee Schedule. Final payment depends on patient-specific cost-sharing, sequestration adjustments, and any quality-program incentives or penalties (such as MIPS) applied at the practice level.