Hyperbaric Oxygen Therapy (HBOT) Insurance Denied

Hyperbaric Oxygen Therapy (HBOT) involves breathing 100% oxygen in a pressurized chamber, raising oxygen levels in the bloodstream and tissues to promote healing and fight infection. While Medicare and most commercial insurers cover HBOT for a defined list of conditions, coverage is frequently denied for off-label uses—and even for covered conditions when documentation is inadequate. Here is how to navigate HBOT coverage.

What Is HBOT and When Is It Used?

During HBOT, patients breathe pure oxygen at pressures 1.5–3 times higher than normal atmospheric pressure, increasing dissolved oxygen in plasma and tissues. This promotes angiogenesis (new blood vessel growth), wound healing, bactericidal activity, and reduction of inflammation.

HBOT is delivered in 60–90 minute sessions, typically 20–40 treatments for most covered conditions. Sessions are conducted in either monoplace chambers (single patient) or multiplace chambers (multiple patients with staff).

Conditions That Are Typically Covered

Medicare's National Coverage Determination (NCD 20.29) covers HBOT for 14 specific conditions, including:

• Chronic non-healing diabetic wounds (most common indication)
• Radiation tissue damage (osteoradionecrosis, radiation cystitis, radiation proctitis)
• Decompression sickness ("the bends")
• Air or gas embolism
• Carbon monoxide poisoning
• Compromised skin grafts and flaps
• Refractory osteomyelitis (bone infection)
• Necrotizing soft tissue infections

Most commercial plans follow Medicare's NCD or apply similar criteria.

Why HBOT Claims Are Denied

Off-Label Use — TBI, Stroke, Autism, and Lyme

The most common denial scenario: HBOT is being used for a condition not on the covered list. Common off-label uses that are routinely denied include:

• Traumatic brain injury (TBI): Despite a growing body of research, HBOT is not yet approved by FDA or covered by most insurers for TBI or post-concussion syndrome
• Autism spectrum disorder: No credible clinical evidence supports HBOT for autism, and these claims are uniformly denied
• Stroke rehabilitation: Evidence is emerging but not yet sufficient for most insurers
• Chronic Lyme disease: Denied as experimental for PTLDS (see our separate guide)
• Long COVID: No established coverage as of 2026, though trials are ongoing

For these conditions, appeals based on medical necessity are possible but face a high bar.

Session Frequency or Count Exceeds Authorization

Even when HBOT is approved, insurers authorize a specific number of sessions upfront (typically 20–30). Extensions beyond the authorized count are frequently denied without updated wound assessment documentation.

Provider Facility Not Covered

HBOT must be performed in an accredited facility. Claims are denied when the facility is not accredited by the Undersea and Hyperbaric Medical Society (UHMS) or is not contracted with the insurer.

Wound Not Meeting Chronicity Criteria

For diabetic wound coverage, insurers require documentation that the wound has been present for at least 30 days and has failed to respond to standard wound care. A wound that has only been treated for 2–3 weeks may not yet meet this threshold.

How to Appeal an HBOT Denial

For Wound Care: Document Chronicity and Failure of Standard Treatment

Your appeal must include a detailed wound history: date of onset, serial wound measurements (size, depth, tissue type), all prior treatments attempted (antibiotics, debridement, advanced dressings, vascular evaluation), and vascular studies confirming adequate blood flow to support healing. Include your wound care specialist's assessment letter.

Reference the CMS NCD language directly: "The determination to use HBO [for diabetic wounds] is based on... the wound must not have responded to 30 days of standard wound care." If your wound meets this criterion, state it explicitly.

For Radiation Injury: Establish the Radiation History

For osteoradionecrosis, radiation cystitis, or proctitis, document: date and site of prior radiation, total radiation dose received, current diagnosis with tissue confirmation if applicable, and evidence of tissue hypoxia or non-healing. Include your radiation oncologist's letter supporting HBOT as appropriate for radiation-induced tissue injury.

For Off-Label Uses: Cite Emerging Evidence

For TBI or stroke, an appeal based on clinical evidence is possible but requires significant support: published peer-reviewed studies (not just case reports), your neurologist's detailed letter explaining why evidence-based alternatives have been exhausted, and functional assessment tools documenting current disability. The FDA has authorized expanded access for some HBOT research protocols—ask your physician if you qualify.

Request Peer-to-Peer With a Wound Care or Hyperbaric Medicine Specialist

UHMS-certified hyperbaric medicine physicians and wound care specialists have the strongest track record in peer-to-peer reviews. The UHMS maintains a directory of board-certified practitioners who can advocate for your coverage.

Session Extension Appeals

For session count extensions, submit updated wound measurements with objective evidence of progress (wound area reduction, improved granulation tissue) alongside your physician's documentation that additional sessions are expected to achieve complete closure.

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Related Reading:

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• What Is Step Therapy?