Hyperbaric Oxygen Therapy CPT Codes: Billing Guide for Providers & Patients

The primary CPT code for hyperbaric oxygen therapy is 99183, which covers physician attendance and supervision of an HBOT session. The facility code is HCPCS G0277, billed in 30-minute segments. Together, these two codes account for nearly all HBOT billing in outpatient and clinic settings. As of 2025, Medicare reimburses physicians approximately $108-$137 per session (99183) and facilities $137.90 per 30-minute segment (G0277).¹²

Primary CPT Code: 99183

CPT code 99183 is defined as “physician or other qualified health care professional attendance and supervision of hyperbaric oxygen therapy, per session.” It is the professional-component code representing the clinical oversight provided during each treatment session.

What 99183 Covers

This code covers the physician’s active, in-person supervision during the session, including monitoring the patient’s physiological response, adjusting treatment parameters as needed, and managing any complications that arise under pressure. It does not cover facility costs, oxygen, or technical staff.

Reimbursement Rates (2025)

The primary HBOT billing code (CPT 99183) reimburses physicians approximately $108-$137 per session, while the facility fee (G0277) adds $137.90 per 30-minute segment.”
PayerPrice.com, verified April 2026; UHMS 2025 CMS Payment Update

Facility Code: HCPCS G0277

G0277 covers “hyperbaric oxygen under pressure, full body chamber, per 30-minute interval.” This is the facility-side code accounting for the chamber, technical staff, monitoring equipment, and overhead. Treatment time runs from start of pressurization to end of depressurization. A typical 90-minute session is billed as 3 units of G0277 ($413.70 in 2025 at Medicare rates).

Hospital Outpatient Code: C1300

C1300 serves the same purpose as G0277 but is used in the hospital outpatient payment system under Ambulatory Payment Classifications (APCs). Also billed in 30-minute increments. Hospitals billing under OPPS use C1300 rather than G0277.

ICD-10 Codes Paired with HBOT Claims

Every HBOT claim must include a diagnosis code matching one of the 15 Medicare-covered indications. Without a matching ICD-10 code, the claim will be denied.

*For diabetic wounds, Medicare requires both a diabetes ICD-10 code and a wound site code. The wound must be Wagner grade III+ and must have failed standard wound therapy before HBOT is approved.

Documentation Requirements for Reimbursement

Insufficient documentation is the leading cause of HBOT claim denials. Every treatment note must include:

• A statement confirming the physician was physically present and actively supervising the session
• Treatment pressure in atmospheres absolute (ATA)
• Oxygen concentration delivered
• Total session duration (start of pressurization to end of depressurization)
• Patient clinical response and any adverse events
• Clinical rationale linking treatment to a covered diagnosis

Prior Authorization

Many commercial insurers and some Medicare Advantage plans require prior authorization before HBOT begins. CMS also operates a prior authorization model for non-emergent HBOT in designated states. Starting treatment before authorization is secured places the provider at financial risk for the entire course.

For wound-related indications, document at least 30 days of standard wound care without adequate improvement before requesting authorization. For diabetic wounds, confirm and document Wagner grade III or higher.

For Patients: Understanding Your HBOT Bill

A typical HBOT bill includes two main charges per session. The physician supervision fee (CPT 99183) covers the doctor who monitored your treatment. The facility or chamber fee (G0277 or C1300) covers the time you spent in the chamber, billed in 30-minute increments. Additional services such as wound debridement appear as separate line items.

Before your first session: ask for the exact CPT and ICD-10 codes your provider plans to submit, confirm coverage and session limits with your insurer, and request prior authorization confirmation in writing. For full insurance coverage details, see our HBOT insurance coverage guide.

Medicare Cost Trends

The G0277 facility rate increased from $132.21 (CY 2024) to $137.90 (CY 2025), while the CMS conversion factor decreased from $33.29 to $32.35 (-2.8%). Physician reimbursement for 99183 decreased 37.8% from 2013 to 2022. Total Medicare cost per 40-session protocol fell 15.6% over the same period, from $27,562 to $23,834.³

Seph Fontane Pennock

Author

Seph Fontane Pennock is the founder of BaricBoost.com and Regenerated.com, a clinic directory for regenerative medicine serving 10,000+ providers across the United States. He previously built and sold PositivePsychology.com, which grew to 19 million users and became the largest evidence-based positive psychology resource on the web. Seph brings direct experience as an HBOT patient, having completed protocols at clinics across three continents while navigating mold illness, systemic inflammation, and autoimmune conditions. His treatment journey includes hyperbaric oxygen therapy, peptide protocols, NAD+ therapy, and consultations with specialists from Dubai to Cape Town to Mexico. This combination of entrepreneurial track record and lived patient experience shapes everything published on BaricBoost.com. Every article is grounded in peer-reviewed research, informed by real clinical encounters, and written for patients making high-stakes treatment decisions. Seph's focus is on bringing transparency, scientific rigor, and practical guidance to the hyperbaric oxygen therapy space.

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