CMS Hyperbaric Oxygen Therapy Coverage Policy Update (NCD 20.29): What Billing Teams Need to Know for 2026

CMS has modified its National Coverage Determination for hyperbaric oxygen (HBO) therapy under NCD 12, with an effective date of March 12, 2026. This policy governs which conditions qualify for Medicare reimbursement when HBO is administered in a chamber setting—and the covered versus noncovered distinctions are strict, specific, and frequently misunderstood by billing teams. If your facility provides HBO therapy, this update warrants an immediate review of your documentation protocols and medical necessity criteria.

What CMS Covers Under the HBO Therapy NCD

CMS defines hyperbaric oxygen therapy for Medicare coverage purposes as a modality in which the entire body is exposed to oxygen under increased atmospheric pressure, administered in a chamber (including single-person units). This is not a blanket coverage policy—reimbursement is tightly limited to 15 specific conditions.

The covered conditions under NCD 12 are:

1. Acute carbon monoxide intoxication
2. Decompression illness
3. Gas embolism
4. Gas gangrene
5. Acute traumatic peripheral ischemia (adjunctive, when loss of function, limb, or life is threatened)
6. Crush injuries and suturing of severed limbs (adjunctive, when loss of function, limb, or life is threatened)
7. Progressive necrotizing infections (necrotizing fasciitis)
8. Acute peripheral arterial insufficiency
9. Preparation and preservation of compromised skin grafts (not for primary wound management)
10. Chronic refractory osteomyelitis, unresponsive to conventional medical and surgical management
11. Osteoradionecrosis as an adjunct to conventional treatment
12. Soft tissue radionecrosis as an adjunct to conventional treatment
13. Cyanide poisoning
14. Actinomycosis—adjunctive only, when refractory to antibiotics and surgical treatment
15. Diabetic wounds of the lower extremities (see specific criteria below)

Several of these indications require HBO to be used as adjunctive therapy—meaning it cannot be billed as a standalone treatment. Documentation must reflect that accepted standard therapeutic measures are being used concurrently.

CMS Medical Necessity Criteria for Diabetic Wound HBO Coverage

Diabetic lower extremity wounds represent the highest-volume indication for HBO therapy in most wound care centers, and they carry the most detailed—and most litigated—coverage criteria in this NCD. CMS requires that all three of the following criteria be met simultaneously:

"Failure" is not a subjective judgment. CMS defines it as no measurable signs of healing for at least 30 consecutive days of standard wound care treatment. Standard wound care, as defined by the policy, includes all of the following:

This is not a checklist you can document retroactively. Each element must be reflected in the clinical record before HBO therapy begins.

Ongoing coverage is not automatic. Once HBO therapy starts, wounds must be evaluated at least every 30 days. If measurable signs of healing have not been demonstrated within any 30-day treatment period, continued HBO therapy is not covered. Billing teams should flag any active HBO cases that are approaching a 30-day evaluation window without documented healing progress—those claims are at significant audit risk.

What CMS Will Not Cover: The Noncovered Conditions List

CMS is explicit: all conditions not listed under the covered section are excluded from Medicare payment. The policy enumerates 12 specific noncovered conditions to remove any ambiguity:

1. Cutaneous, decubitus, and stasis ulcers
2. Chronic peripheral vascular insufficiency
3. Anaerobic septicemia and infection other than clostridial
4. Skin burns (thermal)
5. Senility
6. Myocardial infarction
7. Cardiogenic shock
8. Sickle cell anemia
9. Acute thermal and chemical pulmonary damage (smoke inhalation with pulmonary insufficiency)
10. Acute or chronic cerebral vascular insufficiency
11. Hepatic necrosis
12. Aerobic septicemia

This list is particularly important for facilities that may be treating pressure injuries or venous stasis ulcers alongside diabetic wounds. A decubitus ulcer does not become a covered indication simply because the patient also has diabetes—the wound must be attributable to diabetes and meet the Wagner and standard-therapy-failure criteria.

Benefit Category and Billing Site Context

CMS covers HBO therapy under three benefit categories:

• Incident to a physician's professional service
• Outpatient hospital services incident to a physician's service
• Physicians' services

This matters for billing teams managing multiple sites. Hospital outpatient departments, freestanding wound care centers billing under a physician's service, and physician offices each have distinct billing pathways. Confirm that your facility type aligns with the applicable benefit category before submitting claims.

Affected Codes

The updated NCD 12 policy document does not list specific CPT or HCPCS codes. Billing teams should reference their MAC's local billing guidelines and the CMS Medicare Claims Processing Manual for the applicable procedure codes associated with HBO therapy chamber services. Do not assume codes from prior policy versions remain unchanged—verify with your MAC directly following the March 12, 2026 effective date.

What Your Billing Team Should Do