- What a UHM Actually Is
- Who Certifies It and Where You Test
- Who Qualifies to Sit
- The Three Content Domains
- What the Exam Looks Like on Test Day
- Fee Mechanics and the Two Routes
- What the Published Results Show
- Where UHM-Certified Physicians Work
- Keeping the Certificate Current
- Sequencing Your Preparation Around the Domains
- Frequently Asked Questions
- UHM means Certification in Undersea and Hyperbaric Medicine, a physician subspecialty credential administered through ABPM.
- The exam is 150 single-best-answer, closed-book questions delivered in three one-hour blocks at Pearson VUE.
- The ABPM route totals $2,650; the ABEM route totals $2,215 and is for ABEM diplomates.
- Content spans three domains: Fundamentals, Diving Medicine, and Clinical Hyperbaric Medicine.
What a UHM Actually Is
When physicians say they are "UHM certified," they mean they hold Certification in Undersea and Hyperbaric Medicine. It is a subspecialty credential for physicians who already hold a primary board certification and have completed dedicated training in the medical effects of pressure, diving, and hyperbaric oxygen therapy. It is not a technician credential, a dive-certification card, or an entry-level qualification. It sits on top of an existing specialty, such as emergency medicine or preventive medicine, and signals formal expertise in two overlapping worlds: the physiology and injury patterns of diving, and the clinical use of hyperbaric oxygen in wound care, infection, and emergency indications.
The acronym causes real confusion online, because other, unrelated credentials abbreviate to the same letters. This site covers only the physician subspecialty. If you want the short-form definitions, our pages on what UHM stands for and the meaning of UHM cover the terminology, and what UHM certification is goes deeper on the credential itself.
Who Certifies It and Where You Test
The certificate is administered through the American Board of Preventive Medicine (ABPM), and the examination is delivered at Pearson VUE test centers. There is also a separate application path for physicians certified by the American Board of Emergency Medicine (ABEM); ABEM diplomates apply through ABEM rather than through ABPM. Both routes lead to the same subspecialty credential, but the paperwork, the portal, and the fee schedule differ, so choose your route before you start gathering documents.
ABPM currently describes the examination as annually administered. For 2026, the examination window runs October 12 through November 1. Because this is a single annual window rather than year-round testing, scheduling is a planning problem as much as a study problem. Our guide to UHM exam dates, testing windows, and deadlines walks through the calendar logic.
Who Qualifies to Sit
This is not an exam you can take straight out of medical school. The eligibility structure has several layers, and each one needs documentation:
- Qualifying medical education and unrestricted medical licenses.
- An accepted primary board certification, since UHM is a subspecialty built on a base specialty.
- Training in the subspecialty itself: either a 12-month ACGME-accredited UHM fellowship or an approved COLT pathway.
- Training verification and rules about how much time may have elapsed since training was completed.
The practical advice is to start the verification paperwork early. Fellowship directors, program coordinators, and licensing boards all have to respond, and delays on their side can cost you a year when the exam is only offered once annually. The full checklist lives in our UHM requirements and eligibility guide, and the training side is covered in our UHM training overview.
The Three Content Domains
The current public outline is organized into three domains. Knowing how they differ in character will shape how you study, because they reward different kinds of thinking.
Domain 1: Fundamentals
The scientific base. Candidates must reason from physical and physiological principles rather than recall isolated facts.
- Gas laws and how pressure changes gas volume, partial pressure, and solubility
- Oxygen physiology, including hyperoxia and the basis of oxygen toxicity
- Chamber types, operations, and safety principles
- Mechanisms by which hyperbaric oxygen is thought to act on tissue
Domain 2: Diving Medicine
The injuries and hazards of the underwater environment, and the medical judgment that follows from them.
- Barotrauma across the ears, sinuses, lungs, and other gas-containing spaces
- Decompression illness: recognition, classification, and recompression logic
- Gas-related toxicity and narcosis considerations
- Fitness-to-dive questions and the interaction of chronic disease with diving
Domain 3: Clinical Hyperbaric Medicine
The therapeutic side: who gets hyperbaric oxygen, why, and what can go wrong.
- Accepted indications and the clinical reasoning behind them
- Patient selection, contraindications, and treatment-related complications
- Treatment protocols, monitoring, and managing patients in the chamber
- Integrating hyperbaric therapy with wound care, infection management, and emergency care
For a section-by-section breakdown of what each domain tests, see the complete UHM exam domains guide.
What the Exam Looks Like on Test Day
The examination consists of 150 single-best-answer multiple-choice questions. Single-best-answer means several options may look plausible, and you must choose the one that is most correct for the scenario. That style rewards clinical prioritization rather than simple recall, especially in the diving and clinical domains where the stem usually presents a patient and asks for the next best step or the most likely mechanism.
| Format Element | What to Expect |
|---|---|
| Question count | 150 single-best-answer multiple-choice questions |
| Structure | Three one-hour testing blocks |
| Appointment length | 3 hours 30 minutes, including tutorial and break |
| Reference materials | Closed book |
| Navigation | Completed blocks cannot be revisited |
| Delivery | Pearson VUE test centers |
Two details deserve attention. First, because you cannot return to a finished block, you need a pacing habit that avoids leaving hard questions for a second pass that will never come. Second, the public materials do not verify a policy on initial remote proctoring, adaptive delivery, or an on-screen calculator, so do not assume any of those. Confirm what is allowed in your candidate instructions, and do not build a strategy around a calculator you may not have. Mental-math fluency with pressure and gas-fraction relationships is a sensible safeguard.
If you are weighing how demanding this is, read how hard the UHM exam really is, and for scoring specifics see the UHM passing score explained.
Fee Mechanics and the Two Routes
Cost depends on which route you use, and the structure is split into an application fee and a separate examination fee.
| Route | Application | Examination | Total |
|---|---|---|---|
| ABPM | $500 | $2,150 | $2,650 |
| ABEM (diplomates apply through ABEM) | $470 | $1,745 | $2,215 |
These figures cover the certification pathway itself. They do not include travel to a test center, study materials, or time away from clinical work. For a fuller budget view, including what to expect beyond the board fees, see the UHM certification cost breakdown.
What the Published Results Show
The official 2024 combined ABPM/ABEM pass rate was 94%, or 29 of 31 candidates. Read that carefully. It is a combined figure across both routes, and it is not labeled as first-time-only, so you cannot treat it as the first-attempt pass rate. The sample is also very small: 31 candidates in total, which means a single additional failure or success would noticeably move the percentage. That is a reason for measured optimism rather than complacency. Candidates arrive with fellowship-level training, which is part of why the number is high, but the exam is closed-book, uses single-best-answer items, and cannot be backtracked. Our page on the UHM pass rate and what the data shows discusses how to interpret figures like this responsibly.
Where UHM-Certified Physicians Work
The certification points toward a fairly specific set of employers and roles:
- Hospital-based hyperbaric and wound care centers, where physicians supervise hyperbaric oxygen therapy for approved indications and manage complex wounds.
- Emergency medicine and critical care physicians who add hyperbaric expertise to cover decompression illness and other time-sensitive indications.
- Diving and occupational medicine settings, including commercial diving operations and fitness-to-dive evaluation.
- Military and government programs with undersea medicine missions.
- Academic and training programs, including fellowship teaching roles.
Many physicians combine UHM with a primary practice rather than leaving it, so the credential often adds a medical-director or consultant role instead of replacing a day job. For market detail, see UHM jobs, the UHM salary guide, and the ROI analysis of whether UHM certification is worth it. Compensation varies enough by setting and by how the role is structured that we avoid quoting a single number here.
Keeping the Certificate Current
Certification is not a one-time event. Under the ABPM Continuing Certification Program for 2025-2029, requirements include:
- Annual licensure in good standing.
- 20 Category 1 CME credits, with at least six relevant to the subspecialty.
- 30 longitudinal assessment questions per certificate.
- An annual fee of $150, $175, or $200 depending on the payment quarter.
Your individual certificate's expiration date should be confirmed in your ABPM account rather than assumed from a general rule. The longitudinal questions are a good reason to retain the material after the exam instead of letting it fade.
Sequencing Your Preparation Around the Domains
Because the content is layered, the order you study it in matters more than the total hours. Fundamentals underpins the other two domains, so it should come first; diving and clinical questions routinely assume you can reason from gas laws and oxygen physiology. A workable pattern for a candidate with a few months before the October window:
Fundamentals first
- Rebuild gas-law reasoning until you can work pressure and partial-pressure problems quickly without a calculator
- Review oxygen physiology and chamber safety principles
Diving Medicine
- Drill barotrauma and decompression illness recognition and management logic
- Practice fitness-to-dive scenarios as vignettes
Clinical Hyperbaric Medicine
- Memorize indications, contraindications, and complication management
- Work protocol and monitoring questions
Timed mixed practice
- Simulate three one-hour blocks of roughly 50 questions each, with no going back
Key Takeaway
Do not save practice questions for the end. Because completed blocks cannot be revisited, rehearse commit-and-move-on pacing early, using timed sets on the UHM practice test site, then review misses by domain so weak areas are obvious.
For a fuller plan, see our UHM study guide and the condensed UHM cheat sheet for last-week review. When you are ready to test yourself under realistic conditions, the practice exams at UHM Exam Prep are built around the same single-best-answer style.
Frequently Asked Questions
It stands for Certification in Undersea and Hyperbaric Medicine, a physician subspecialty credential administered through the American Board of Preventive Medicine. It is distinct from other credentials that happen to share the same acronym.
There are 150 single-best-answer multiple-choice questions in three one-hour blocks. The exam is closed-book, and once a block is complete you cannot return to it.
The ABPM route is a $500 application fee plus a $2,150 examination fee, for $2,650 total. The ABEM route is $470 plus $1,745, or $2,215 total, and ABEM diplomates apply through ABEM.
Eligibility includes 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 also apply.
The 2026 examination window runs October 12 through November 1, and ABPM currently describes the exam as annually administered. Confirm deadlines in your ABPM account before planning.
For a broader orientation to the credential, you can also revisit what UHM is and the overview of UHM certification.