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Denied claims due to unauthorized patient procedures or services can be a major loss in revenue. Although most medical offices and provider based departments are moving closer to 100 percent verification for patient services, there is still no guarantee that every account will be paid. Claims that are denied due to no prior authorization happen primarily in a hospital setting. To ensure your claims will be paid, plan ahead, meticulously document, and follow regulations as noted below. 


The coding of HBOT is represented by 2 separate CPT codes 99183 and G0277.  HCPCS defines CPT code 99183 as Physician or other qualified health care professional attendance and supervision of hyperbaric oxygen therapy, per session. 99183 represents the professional component of the hyperbaric treatment and can only be billed as 1 unit.

??- Physician or non physician practitioner must be immediately available to assist and direct performance of procedure -

The word supervision must be emphasized here.  According to Federal Register 42 CFR, Direct supervision means that the physician or non-physician practitioner must be immediately available to furnish assistance and direction throughout the performance of the procedure. The physician is not required to be present in the room where the procedure is performed or within any other physical boundary as long as he or she is immediately available.

HCPCS defines CPT code G0277 as hyperbaric oxygen therapy, full body chamber, per 30 minutes. G0277 represents the facility component of the hyperbaric treatment. It is important to understand the 30-minute increment language and how it relates to prior authorization of HBOT.

?- The 30-minute increments language in regulations is critical to understand for prior authorization of HBOT -

?The following example will illustrate this: the hyperbaric provider has consulted on the patient and determined that a course of 30 treatments will be needed for Soft Tissue Radionecrosis.  The nurse or technologist clarifies the ICD-10 diagnoses with the HBO physician and gathers the clinical data to present to the carrier for prior authorization of services. 

The following steps are important and necessary to ensure that both the physician and facility are paid for services.

  1. Verify coverage and benefits with the insurance carrier. Ask: "Does the patient have active coverage, is this insurance the primary and when does the plan expire?"
  2. Verify that the patient’s plan provides coverage for HBOT. It is important to provide them with the CPT codes, 99183 and G0277.
  3. Ask if codes 99183 and G0277 require prior authorization. If authorization is required, provide the number of units you will need for each CPT code
    1. If you are requesting 30 HBO treatments, the authorization request for 99183 would be 30 units.  
    2. If you are requesting 30 HBO treatments, the authorization request for G0277 would be for the number of 30 minute increments multiplied by the number of requested treatments which in this case would be 120 units. 1 hyperbaric treatment is typically billed as four 30-minute increments. 
    3. See table below for G0277 billing increments.
  4. Ask the representative to refer to their coverage determination on HBOT and ask if they cover the indication which in this case is STRN.
  5. Obtain a copy of the carrier’s coverage determination for HBOT prior to beginning therapy and highlight the indication and ICD-10 codes relevant to this authorization.
  6. Request a date span which will allow time for 30 HBO treatments to be administered. In this case, 60 days would be sufficient.
  7. Once authorization is given, document all of the above information clearly and thoroughly. This will include:
    1. The authorization number
    2. Number of treatments authorized
    3. Authorization start and end date
    4. Time, date and name of the person you spoke with
    5. A reference number that has been assigned to this phone call or case 
    6. Request a faxed copy of the authorization 
  8. Remind the patient that is is also their responsibility to make contact with their insurance company to ensure coverage i.e., deductible, copay, coinsurance and maximum out of pocket expense.
  9. Communicate the HBO Authorization number and details to the billing department.

G0277- Hyperbaric Time Increments



0 - 15


16 - 45


46 - 75


76 - 105


106 - 135


136 -165


166 - 195


196 - 225


226 - 255


256 - 285


286 - 315


316 - 345


346 - 375


376 - 405



Recently, a hyperbaric facility received a denial notice on the explanation of benefits for hyperbaric treatments 11-40 specifically, the G0277 code. When the staff inquired as to why with United Health Care, they were informed that during the prior authorization process, they had requested authorization for 40 hyperbaric treatments. As of 10th hyperbaric treatments, UHC had already paid for 40 units of G0277 leaving the facility with a deficit of 120 units or 30 total treatments still to be paid.  This would account for about $24,000 of lost revenue for one patient.

Avoiding lost revenue for HBOT is paramount in running a successful program

A systematic approach and meticulous documentation can ensure that your facility receives payment for all services provided


A HBOT prior authorization form template is provided here for reference (open access, after creating free account). 

The WoundReference Hyberbaric Oxygen Therapy Knowledge Base features guidelines to promote high standards of patient care and operational safety within the hyperbaric program and other important tools. The WoundReference Curbside Consult gives you actionable, specific answers from our expert panel in a timely manner. 

For customized safety programs and other wound care and hyperbaric medicine consultation services, visit MidWest Hyperbaric


We thank Julie Rhee ScM, for style editing

About the Authors

With over four decades of healthcare experience, Jeff currently holds the position of Principal Partner at Midwest Hyperbaric LLC and the Co-founder and Chief Clinical Officer of Wound Reference. Jeff has excelled in critical care throughout his career, devoting almost a decade as a Flight Respiratory Therapist/Paramedic for the Spirit of Kansas City Life Flight. In 1993, Jeff transitioned into the field of Hyperbaric Medicine and Wound Care, where he committed 21 years of his career to serving as the Program Director for a 24/7 Level 1 UHMS Accredited facility with Distinction. In this role, he continued to provide patient care while overseeing all administrative, clinical, and daily operations within the Wound Care and Hyperbaric Facility. Jeff is a Registered Respiratory Therapist and a Certified Hyperbaric Technologist (CHT). He has also undergone training as a UHMS Safety Director and a UHMS Facility Accreditation Surveyor. Jeff currently serves as a member of the UHMS Accreditation Council, the UHMS Accreditation Forum Expert Panel, and the UHMS Safety Committee. Additionally, he is an esteemed member of the NFPA 99 Hyperbaric and Hypobaric Facilities Technical Standards Committee. Jeff's dedication to the field has earned him numerous prestigious awards. In 2010, he received the Gurnee Award, which honored his outstanding contributions to undersea and hyperbaric medicine. Three years later, in 2013, he was awarded the Paul C. Baker Award for his commitment to Hyperbaric Oxygen Safety Excellence. Most recently, in 2020, Jeff was honored with "The Associates Distinguished Service Award (UHMSADS)," a recognition reserved for exceptional Associate members of the Society who have demonstrated exceptional professionalism and contributions deserving of the highest accolades.
An Advanced Certified Hyperbaric Registered Nurse and Certified Wound Specialist with expertise in billing, coding and reimbursement specific to hyperbaric medicine and wound care services. UHMS Accreditation Surveyor and Safety Director. Principal partner of Midwest Hyperbaric LLC, a hyperbaric and wound consultative service. Tiffany received her primary and advanced hyperbaric training through National Baromedical Services in Columbia South Carolina. In 2021, Tiffany received the UHMS Associate Distinguished Service Award. "This award is presented to individual Associate member of the Society whose professional activities and standing are deemed to be exceptional and deserving of the highest recognition we can bestow upon them . . . who have demonstrated devotion and significant time and effort to the administrative, clinical, mechanical, physiological, safety, technical practice, and/or advancement of the hyperbaric community while achieving the highest level of expertise in their respective field. . . demonstrating the professionalism and ethical standards embodied in this recognition and in the UHMS mission.”
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