- What This Credential Actually Is
- Who Certifies You and Where You Test
- Eligibility and Training Pathways
- Exam Format: 150 Questions in Three Blocks
- The Three Content Domains
- Fees and Registration Mechanics
- Reading the Published Pass Rate
- Sequencing Your Preparation by Domain
- Who Hires Certified Physicians
- Maintaining Certification: The CCP Cycle
- Frequently Asked Questions
- The exam is administered by ABPM at Pearson VUE: 150 single-best-answer questions across three one-hour blocks.
- ABPM route costs $2,650 total ($500 application plus $2,150 exam); the ABEM route totals $2,215.
- Eligibility requires a 12-month ACGME UHM fellowship or an approved COLT pathway, plus unrestricted licenses.
- Completed blocks cannot be revisited, so pacing and first-pass accuracy matter more than second-guessing.
What This Credential Actually Is
Certification in Undersea and Hyperbaric Medicine is a subspecialty credential for physicians who already hold a primary board certification. It recognizes expertise in two linked areas: the physiology and medical management of divers and compressed-gas workers, and the clinical use of hyperbaric oxygen therapy in hospital and wound-care settings. If you are still sorting out terminology, our explainers on what UHM certification is and what UHM stands for cover the basics.
This article is about this specific credential only. The "UHM" acronym is used elsewhere in other fields, and nothing here applies to those. Everything below concerns the physician subspecialty examination in undersea and hyperbaric medicine.
Who Certifies You and Where You Test
The American Board of Preventive Medicine (ABPM) administers the examination, and testing takes place at Pearson VUE test centers. Physicians certified through the American Board of Emergency Medicine (ABEM) take a separate route: ABEM diplomates apply through ABEM rather than ABPM, and the fee structure differs, as shown in the comparison table below.
Because the board that processes your application depends on your primary certification, confirm your route before you pay anything. A mistaken application to the wrong board wastes time against a tight annual window.
Eligibility and Training Pathways
The eligibility picture has several layers, and each one needs documentation. Candidates generally must show:
- Qualifying medical education from an accepted program.
- Unrestricted medical licenses, meaning no active restrictions that would limit practice.
- An accepted primary board certification, since this is a subspecialty credential built on top of an existing specialty.
- Completion of a 12-month ACGME-accredited UHM fellowship, or an approved COLT pathway as the alternative route to demonstrating training.
Training verification is a real step, not a formality. Your program must confirm your training, and elapsed-training reference rules apply, which means the time since you completed training can affect how your application is evaluated. If you finished fellowship some years ago, read the current rules carefully before assuming you qualify. Our full breakdown in UHM Requirements 2026: Eligibility, Prerequisites & How to Qualify walks through documentation in more detail.
Key Takeaway
Start the training-verification paperwork months before the application opens. Delays in obtaining a program director's confirmation are a common reason candidates miss a testing window, and ABPM currently describes the exam as annual.
Exam Format: 150 Questions in Three Blocks
The examination consists of 150 single-best-answer multiple-choice questions delivered in three one-hour testing blocks. The full appointment lasts 3 hours 30 minutes, which includes the tutorial and a break. It is closed-book.
The most important structural rule is that once you complete a block, you cannot go back to it. That changes how you should work:
- Commit within each block. Use the full hour to flag and revisit questions inside the current block, but treat the block's end as final.
- Budget roughly even pacing. With 150 questions across three blocks, plan for a steady rate rather than front-loading time on difficult items.
- Do not rely on assumptions about tools. There is no verified policy confirming initial remote delivery, adaptive testing, or calculator availability, so confirm current conditions with ABPM and Pearson VUE before test day instead of assuming.
For a sense of how the format feels against the content, see How Hard Is the UHM Exam? Complete Difficulty Guide 2026, and for scoring questions see UHM Passing Score 2026.
The Three Content Domains
The current public outline has three domains. Knowing how they differ in character helps you allocate study time sensibly. The complete treatment lives in UHM Exam Domains 2026: Complete Guide to All 3 Content Areas; here is the practical orientation.
Domain 1: Fundamentals
The scientific base that underlies everything else. Expect questions that test whether you understand why pressure changes affect the body, not just that they do.
- Gas laws and their application to pressure, volume, and partial pressure
- Physiology of oxygen, nitrogen, and other gases under pressure
- Chamber types, operations, and the physical environment of treatment
- Oxygen toxicity mechanisms and the principles behind hyperoxic therapy
Domain 2: Diving Medicine
The occupational and recreational diving side of the specialty, including injuries that happen at depth and on ascent.
- Decompression illness: arterial gas embolism versus decompression sickness, and how to distinguish them
- Barotrauma of the ears, sinuses, lungs, and other gas-containing spaces
- Fitness-to-dive evaluation and the medical conditions that complicate it
- Inert gas narcosis, breathing-gas considerations, and dive-related emergencies
Domain 3: Clinical Hyperbaric Medicine
The therapeutic domain: who gets hyperbaric oxygen, on what protocol, and with what monitoring.
- Accepted indications and the clinical reasoning for treatment selection
- Treatment protocols, scheduling, and response assessment
- Contraindications, complications, and patient safety during therapy
- Integration with wound care, infection management, and other hospital services
Questions are single-best-answer, so the work is often discriminating between several plausible choices. In diving medicine especially, candidates should expect clinical vignettes where timing, depth, and symptom pattern determine the correct answer.
Fees and Registration Mechanics
Costs differ by board route. The figures below come from the published fee structures.
| Route | Application Fee | Examination Fee | Total |
|---|---|---|---|
| ABPM | $500 | $2,150 | $2,650 |
| ABEM (diplomates apply through ABEM) | $470 | $1,745 | $2,215 |
Beyond the exam itself, budget for any fellowship-related documentation costs, travel to a Pearson VUE center, and study materials. The 2026 examination window is October 12 to November 1, so plan registration deadlines backward from that range. For the complete financial picture, including how the cost compares with career returns, see UHM Certification Cost 2026: Complete Pricing Breakdown and UHM Exam Dates 2026 for scheduling detail.
Reading the Published Pass Rate
The official 2024 combined ABPM/ABEM pass rate was 94%, which was 29 of 31 candidates. Two cautions apply when interpreting it.
- Small cohort. With only 31 examinees, a difference of one or two candidates moves the percentage substantially. Treat it as a rough signal, not a precise forecast.
- Not labeled first-time-only. The published figure is not identified as limited to first-time takers, so you cannot assume it reflects first-attempt performance.
A high pass rate for a self-selected group of fellowship-trained physicians does not mean the exam is trivial. These candidates have already completed a dedicated year of focused training. See UHM Pass Rate 2026: What the Data Shows for a fuller reading of the numbers.
Sequencing Your Preparation by Domain
Rather than a generic schedule, tie your calendar to how the domains build on each other. Fundamentals underpins both of the others, so it goes first. A sample structure for a candidate working back from the October window:
Fundamentals first
- Rebuild gas-law and physiology reasoning until you can apply it to novel scenarios
- Review chamber operations and oxygen toxicity mechanisms
Diving Medicine
- Drill the arterial gas embolism versus decompression sickness distinction using case vignettes
- Cover barotrauma by anatomical site and fitness-to-dive decision-making
Clinical Hyperbaric Medicine
- Organize indications, protocols, and contraindications into a single comparative framework
- Practice treatment-selection questions where several options seem reasonable
Timed block practice
- Simulate the one-hour block format and practice committing to answers without returning
- Review missed items by domain to find recurring weak spots
For more on structuring this, see the UHM Study Guide 2026: How to Pass on Your First Attempt, and use the UHM Cheat Sheet 2026 for final-week review. When you are ready to test yourself under realistic conditions, our UHM practice tests are built around the three-domain structure.
Who Hires Certified Physicians
Demand for this credential comes from a fairly defined set of employers and settings:
- Hospital-based hyperbaric and wound-care centers that need a qualified medical director to oversee treatment programs.
- Multi-site wound-care management companies that staff hyperbaric departments across many facilities.
- Diving and occupational medicine programs, including those serving commercial, military, and research diving communities.
- Academic medical centers that combine clinical service, teaching, and research in the field.
Many physicians combine hyperbaric work with a primary specialty such as emergency medicine, so the certification often adds a defined role alongside existing practice rather than replacing it. Explore current openings and role types in UHM Jobs, and weigh earnings and value in the UHM Salary Guide 2026 and Is the UHM Certification Worth It?.
Maintaining Certification: The CCP Cycle
Passing the exam is not the end of the obligation. Certification is maintained through the Continuing Certification Program (CCP), and the 2025-2029 cycle sets these requirements:
- Annual licensure: maintain a valid license each year.
- 20 Category 1 CME credits, including at least six that are relevant to the specialty.
- 30 longitudinal assessment questions per certificate.
- Annual fee of $150, $175, or $200 depending on the payment quarter.
Expiry dates for individual certificates vary, so confirm yours through your ABPM account rather than relying on a general rule. Building CME in hyperbaric topics each year makes the six-credit relevance requirement painless.
Frequently Asked Questions
ABPM administers it at Pearson VUE test centers. Physicians certified through ABEM follow a separate route and apply through ABEM, with a different fee structure of $470 plus $1,745, totaling $2,215.
There are 150 single-best-answer multiple-choice questions in three one-hour blocks. The appointment runs 3 hours 30 minutes including the tutorial and a break. Completed blocks cannot be revisited.
The current public outline lists three domains: Fundamentals, Diving Medicine, and Clinical Hyperbaric Medicine. See the domains guide for what each covers.
You need qualifying medical education, unrestricted licenses, an accepted primary certification, and either a 12-month ACGME UHM fellowship or an approved COLT pathway. Training verification and elapsed-training rules apply.
The 2026 examination window runs October 12 to November 1. ABPM currently describes the exam as administered annually, so a missed window typically means waiting for the next cycle.
The official 2024 combined ABPM/ABEM pass rate was 94%, or 29 of 31 candidates. The cohort is small and the figure is not labeled first-time-only, so interpret it cautiously.