The short answer: CPT 99183 pays a physician or qualified provider about $110 per session (2026 Medicare national) for attendance and supervision of hyperbaric oxygen therapy. The facility bills G0277 per 30 minutes, roughly $138 (2025). Both need a Medicare-covered, FDA-cleared diagnosis. Wellness HBOT has no billing code: it is cash-pay.
Disclosure: Superhuman Chambers manufactures and sells hyperbaric chambers for wellness operators. This article is general education, not billing, legal, or medical advice. Rates change annually; verify current figures with CMS and your MAC.
Search “hyperbaric chamber CPT code” and you will find 99183 and G0277 quoted side by side, usually with conflicting dollar figures and at least one page that gets the basic mechanics wrong. The confusion is structural: hyperbaric billing splits into a professional component and a facility component, paid through two different Medicare fee schedules, by two different entities, on two different claim forms. This guide decodes both codes with the actual 2025–2026 numbers, covers the rules that decide whether claims survive an audit, and then asks the question nobody else in the search results does: what if billing insurance is simply not your model?
The HBOT billing codes at a glance
| Code | Short descriptor | Who bills | Unit | Medicare national rate (year) |
|---|---|---|---|---|
| CPT 99183 | Physician/QHP attendance and supervision of HBOT | Physician or qualified health care professional | Per session, any length | $109.55 (CY 2026); $102.21 (CY 2025) |
| HCPCS G0277 | Hyperbaric oxygen under pressure, full body chamber | Hospital outpatient facility | Per 30-minute interval | $137.90 (CY 2025); about $141.50 est. (CY 2026) |
| HCPCS C1300 | Historical predecessor of G0277 | Hospital outpatient facility | Per 30 minutes | Discontinued January 1, 2015 |
| CPT 99184 | Neonatal hypothermia (not hyperbaric) | Physician | Per procedure | n/a, disambiguation only |
The rest of this article walks each row.
What CPT 99183 actually covers
The official descriptor, decoded
The AMA descriptor for CPT 99183 reads: “Physician or other qualified health care professional attendance and supervision of hyperbaric oxygen therapy, per session.” Every word does work. It is a professional component code: it pays the clinician, not the clinic. The chamber, the oxygen, the technician, the overhead, none of that is inside 99183. What Medicare buys with this code is the presence and oversight of a physician or qualified health care professional during treatment.
At roughly $109.55 per session (CY 2026 national, non-facility), 99183 alone can never fund a hyperbaric program. Everything physical about the treatment is paid elsewhere, which is where G0277 comes in.
Per session, not per minute
99183 is billed once per session regardless of session length. A 60-minute dive and a 120-minute dive each generate one unit. This sounds obvious, yet at least one prominent billing company describes 99183 as a time-based code billed per 30-minute unit, which is simply wrong and would inflate professional claims if anyone followed it. The per-30-minute logic belongs to G0277. Mixing the two unit systems is one of the most common HBOT billing errors, and one of the easiest for an auditor to spot.
99183 vs 99184: not the same neighborhood
One disambiguation, because code-lookup tools surface them together: CPT 99184 is not a hyperbaric code at all. It covers initiation of selective head or total body hypothermia in critically ill neonates, per Aetna’s clinical policy bulletin. If a “related codes” panel suggests 99184 for your chamber claim, the panel is wrong.
G0277 vs 99183: facility money vs physician money
Where G0277 lives
HCPCS G0277 carries the descriptor “hyperbaric oxygen under pressure, full body chamber, per 30 minute interval.” It is the facility or technical component, billed by hospital outpatient departments under the Outpatient Prospective Payment System on the UB-04 claim form. G0277 replaced the older HCPCS C1300 effective January 1, 2015, which matters because some vendor blogs still reference C1300 a decade after it died.
Unit counting runs from the start of pressurization to the end of depressurization. A typical 90-minute treatment generates 3 units of G0277. This is the code that pays for the chamber, the oxygen, and the technical staff, which is why facility revenue dwarfs the professional fee.
What a 90-minute session looks like on paper
Here is the worked example, with our math and the years labeled, at Medicare national rates:
- 1 × CPT 99183 (professional supervision) = $109.55 (CY 2026)
- 3 × HCPCS G0277 (facility, 30-minute intervals) = 3 × $137.90 (CY 2025) = $413.70
- Total: approximately $523 per 90-minute session
Two caveats. This deliberately mixes fee schedule years because the verified G0277 figure is the CY 2025 rate; treat the total as an order of magnitude, not a quote. And national rates are the midpoint: locality adjustments move both figures in practice.
What Medicare pays: 2025–2026 numbers
99183 fee schedule figures and locality variation
On the Physician Fee Schedule, the national non-facility rate for 99183 is $109.55 for CY 2026 (Q1–Q3), up from $102.21 in CY 2025, with a work RVU of 2.06 and total RVUs of 3.28, per MedFeeSchedule and RVUinUSA. Locality-adjusted amounts quoted in billing guides run roughly $108–$137 depending on your Geographic Practice Cost Index. Commercial and all-payer averages are higher, around $174–$195, but that figure comes from a single secondary source, so treat it as directional.
G0277 OPPS rates and the 2026 bump
The OPPS national rate for G0277 was $132.21 in CY 2024 and $137.90 in CY 2025, per the UHMS payment update. The CY 2026 OPPS final rule raises hospital outpatient rates by 2.6%, which implies roughly $141.50 per interval for CY 2026, but we have not verified the published CY 2026 G0277 line item directly, so treat that figure as an estimate derived from the Federal Register percentage, nothing more.
The 10-year trend points down
Before you build a pro-forma on these numbers, look at the trajectory. A 2024 analysis in Undersea & Hyperbaric Medicine (Gelly, Fife, et al., PMID 38985150) found that physician reimbursement for 99183 fell 37.8% from 2013 to 2022, and total Medicare cost per 40-session protocol fell 15.6%, from $27,562 to $23,834. Medical hyperbarics is a shrinking-fee business at the federal level. That belongs in any honest operator model.
Who may bill: coverage, supervision, documentation
NCD 20.29’s 15 covered indications
Both codes require a Medicare-covered diagnosis. The controlling document is National Coverage Determination 20.29, which lists 15 covered indications, from air embolism and carbon monoxide poisoning to diabetic lower-extremity wounds (added effective April 1, 2003, at Wagner grade III or higher after failed standard therapy). Everything not on the list is non-covered, full stop. We lay out the indication landscape, and why the FDA, UHMS, and Medicare lists all count differently, in our FDA-cleared indications guide; the patient-facing side of who pays for what is in our HBOT insurance coverage guide.
Claims submitted outside the NCD list are denied, and off-list billing is a known audit trigger. There is no creative coding path around this.
Supervision after 2020: general on paper, attendance in the descriptor
Public sources genuinely conflict here, so the careful version. The CY 2020 OPPS final rule changed the minimum supervision level for hospital outpatient therapeutic services from direct to general supervision: overall direction and control, no physical presence required. Three things complicate the simple reading. HBOT sits in the “non-surgical extended duration therapeutic services” category, whose post-pandemic status is fuzzy in public sources. In physician offices, supervision remains direct. And the 99183 descriptor still says “attendance and supervision,” so billing it implies the physician or QHP attended the session regardless of the facility-level rule. Intellicure’s supervision analysis is the clearest public treatment of this.
The safe summary: the regulatory floor in hospital outpatient departments has been general supervision since 2020, but the 99183 descriptor still requires physician attendance, many facilities keep direct-supervision policies, and your MAC’s Local Coverage Determination controls the paperwork. Verify with your MAC before assuming anything.
Documentation that survives an audit
LCD-level documentation expectations are consistent across sources. Every treatment note needs:
- A physician supervision statement
- Treatment pressure in ATA
- Oxygen concentration
- Session duration, from pressurization start to depressurization end
- Patient response to treatment
- Clinical rationale tied to the covered ICD-10 diagnosis
For diabetic wounds, expect to document Wagner grade III or higher, at least 30 days of failed standard wound therapy, and measurable healing progress for continued coverage. Many commercial payers and some Medicare Advantage plans also require prior authorization. Staffing the technical side of a compliant program is its own discipline; see our hyperbaric technician certification guide for the CHT and CHRN landscape.
Why wellness centers do not bill insurance
No covered indication, nothing to bill
The FDA’s consumer page on HBOT states plainly that hyperbaric devices are cleared for 13 disorders and are not proven for cancer, Lyme disease, autism, or Alzheimer’s. Wellness use cases (athletic recovery, general longevity, cognitive performance, anti-aging) appear on no coverage list anywhere. There is no code, no diagnosis, and no claim to file. Cash-pay is the model by design, not by omission.
Mild 1.3 ATA sits outside the universe entirely
Most wellness HBOT runs at 1.3 ATA, often in soft-shell chambers. The FDA page adds a pointed note: zippered soft chambers are cleared for altitude sickness only and not for use with oxygen tanks or concentrators. The clinical evidence and every billing rule in this article live at 2.0 ATA and above in hard chambers under physician supervision. Mild wellness HBOT is not a lower tier of the medical system; it is a different industry that shares the hardware category.
Cash-pay pricing reality
Directional market data puts wellness HBOT sessions at roughly $150–$600+ per session (2025–2026 market ranges), with soft-shell sessions around $50–$100 and hard-shell mid-pressure sessions around $150–$250, usually sold in packages. These figures come from consumer pricing guides, not fee schedules, so treat them as orientation, not rate cards.
What this means for your operator pro-forma
If you are scoping a hyperbaric business, the 99183/G0277 system is not just a billing topic. It is a fork in the business model, and the two paths have almost nothing operational in common.
| Dimension | Medical HBO facility model | Cash-pay wellness model |
|---|---|---|
| Billing codes | 99183 + G0277 | None; no codes exist |
| Diagnosis required | One of NCD 20.29’s 15 covered indications | No diagnosis; contraindication screening instead |
| Typical pressure | 2.0 ATA and above | 1.3–2.0 ATA |
| Physician role | Attendance and supervision per the 99183 descriptor | Screening and protocol oversight by policy, not by code |
| Revenue per 90-min session | About $523 Medicare total (2025/2026 national, mixed years) | $150–$600 cash (directional market range) |
| Payer relationship | Claims, prior auth, denials, audits | Direct payment, no claims |
| Compliance burden | LCD documentation, accreditation, MAC audit exposure | Marketing-claims rules, device status, local regulation |
A decision checklist before you commit to either path:
- Does your target client pool actually carry NCD 20.29 covered diagnoses, referred by physicians?
- Do you have, or can you contract, a physician or QHP willing to attend sessions under the 99183 descriptor?
- Can your operation absorb prior authorization, LCD-grade documentation, and audit exposure as fixed costs?
- Does your local market support cash pricing in the $150–$600 range without a reimbursement story?
- Is your chamber’s pressure tier consistent with what your marketing can credibly claim?
The full economics of each path, including payback modeling and staffing, are laid out in our hyperbaric chamber business guide. What we see across operators is consistent: the businesses that struggle assumed medical-model revenue on a wellness-model license, or vice versa. The billing codes tell you which world you are in before you sign anything. If you are scoping a wellness build-out and want a second set of eyes on the model, talk to our team.
FAQ
What is the CPT code for hyperbaric oxygen therapy?
There are two. CPT 99183 is the professional code: provider attendance and supervision, billed once per session. HCPCS G0277 is the facility code: the chamber treatment itself, billed per 30-minute interval. Most treatments involve both, billed by different entities on different claim forms.
What is the difference between 99183 and G0277?
99183 pays the clinician for supervising; G0277 pays the facility for delivering. 99183 is per session at about $109.55 (CY 2026 Medicare national); G0277 is per 30 minutes at $137.90 (CY 2025 OPPS national). A 90-minute session typically generates one unit of 99183 and three units of G0277.
Can 99183 be billed for sessions shorter or longer than 90 minutes?
Yes. 99183 is per session, so length does not change the unit count: one session, one unit. What changes with length is the G0277 count, one unit per 30-minute interval from pressurization start to depressurization end.
Does Medicare cover hyperbaric oxygen therapy?
Yes, but only for the 15 indications listed in NCD 20.29, including air embolism, carbon monoxide poisoning, crush injury, problem wounds, and qualifying diabetic lower-extremity wounds. Everything outside that list is non-covered, and wellness use matches nothing on it.
Can a wellness center bill insurance for HBOT?
No, practically speaking. Insurance billing requires a covered diagnosis, a cleared indication, and physician supervision documented to LCD standards. Wellness sessions have none of these. The wellness model is cash-pay, and its compliance work is marketing-claims discipline rather than claims submission.
Limitations and notes
Rates here are national Medicare figures labeled by year; your locality-adjusted amounts will differ, and every figure resets each January. The CY 2026 G0277 estimate is derived from the published 2.6% OPPS increase, not a verified line item. Supervision rules vary by setting, facility policy, and MAC, and the post-pandemic status of extended-duration services is genuinely unclear in public sources. Nothing here is billing, legal, or medical advice: before billing anything, talk to a certified professional coder and confirm current rules with CMS and your Medicare Administrative Contractor.
References
- Centers for Medicare & Medicaid Services. NCD 20.29: Hyperbaric Oxygen Therapy.
- MedFeeSchedule. CPT 99183 fee schedule figures (CY 2025 and CY 2026 national rates).
- RVUinUSA. CPT 99183 RVU breakdown (work RVU 2.06, total 3.28).
- Pabau. HCPCS G0277 guide (descriptor, C1300 replacement in 2015, UB-04 billing).
- Federal Register. CY 2026 OPPS/ASC final rule (2.6% rate increase).
- Gelly HB, Fife CE, et al. Undersea & Hyperbaric Medicine, 2024. PMID 38985150 (99183 reimbursement trend, 2013–2022).
- Intellicure. Hyperbaric oxygen therapy chamber supervision (2020 supervision change, setting differences).
- AAPC. Dive deeper into HBO therapy in wound care centers (15 NCD indications, LCD documentation).
- U.S. Food & Drug Administration. Hyperbaric Oxygen Therapy: Get the Facts (cleared indications, soft-chamber limits).
- Aetna. Clinical Policy Bulletin 0812 (99184 neonatal hypothermia disambiguation).
- Hyperbaric Business Solutions. CPT codes for hyperbaric oxygen therapy (per-session semantics, unit counting).
- BaricBoost. HBOT CPT codes and billing (locality rate ranges; UHMS G0277 figures; its C1300 reference is outdated).