One of the most common Medicare billing issues in HBOT is failure to meet coverage requirements under NCD 20.29, particularly related to non‑covered diagnoses. Medicare strictly limits HBOT to a defined list of conditions, and claims will be denied if the diagnosis does not match or if HBOT is used as a primary rather than adjunctive therapy. A high-risk area is diabetic wounds, where all criteria must be met (Type I/II diabetes, Wagner Grade III or higher), and documented failure of at least 30 days of standard wound care with no measurable improvement. A frequent provider pitfall is initiating HBOT too early without sufficient documentation of failed conservative treatment, resulting in avoidable denials.