- UHM refers to AOA Subspecialty Certification in Undersea and Hyperbaric Medicine, a distinct osteopathic credential.
- The written exam has 150 multiple-choice questions across four domains, with Fundamentals weighted heaviest at 40%.
- Passing requires a scaled score of at least 500 on a 200-800 scale.
- Exam and recertification fees are each $1,100.
What UHM Actually Means in This Context
UHM, in the context this site covers, stands for the AOA Subspecialty Certification in Undersea and Hyperbaric Medicine. This credential is administered under the American Osteopathic Conjoint Undersea & Hyperbaric Medicine Examination Committee, operating within the American Osteopathic Association's board certification structure. It is important to be precise here because "UHM" is used by more than one organization in medicine, and the requirements, fees, and exam structure differ depending on which body issues the credential. This article - and everything else on UHM Exam Prep - focuses exclusively on the AOA initial written examination pathway, not any separate ABPM or ABEM examination track.
If you arrived here searching for a general definition, you may also find our companion pieces useful: UHM Meaning, What Does UHM Stand For?, and What Is A UHM? all address the terminology question from slightly different angles, while this page goes deeper into the certification mechanics.
Who Administers This Certification
The certifying authority is the American Osteopathic Conjoint Undersea & Hyperbaric Medicine Examination Committee, working within the broader AOA subspecialty certification framework. This is not a standalone board; it functions as a conjoint committee that reviews applications, sets the written examination, and manages the ongoing certification (OCC) pathway for physicians who already hold primary board certification in one of four osteopathic specialties. The official examination page is maintained by the American Osteopathic Association's certification division, and candidates should always verify current dates and fee schedules directly at the source, since published scheduling text on that page has, at times, lagged behind the current cycle.
Eligibility Pathway
Eligibility for this UHM certification is built around a sequence of training and licensure milestones rather than a single test-day requirement. Published eligibility criteria include:
- A medical degree from a COCA-accredited osteopathic medical school
- Completion of a one-year AOA-approved internship
- Completion of a one-year AOA- or ACGME-approved hyperbaric medicine fellowship
- Primary board certification through AOBEM, AOBFP, AOBIM, or AOBPM
- Unrestricted medical licensure and good ethical standing
The application itself is documentation-heavy. Candidates must submit a CV, proof of licensure, fellowship completion records, and - notably - documentation of supervised treatment volume. Specifically, applicants must demonstrate supervision of at least 500 treatments, distributed across the 13 treatment indications specified in the published requirements, according to institutional case frequency. This distribution requirement means fellows and early-career candidates should track case logs by indication throughout training rather than trying to reconstruct them later. For a full breakdown of every prerequisite and how to document them, see UHM Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Key Takeaway
Start logging supervised treatments by indication during your fellowship year - reconstructing 500 treatments across 13 categories after the fact is far harder than tracking them in real time.
Exam Format and Scoring
The written examination consists of 150 multiple-choice questions covering four defined content areas. Passing requires a scaled score of at least 500 on a 200-800 scale - this is not a raw percentage-correct cutoff, so candidates should not try to estimate their result using simple item-count math. For a complete explanation of how the scaled scoring works and what it means for how many questions you can miss, review UHM Passing Score 2026: Exactly What You Need to Pass.
Because the exam draws from a defined four-category outline published on the official examination page, question style tends to be case-based and applied rather than pure recall - expect scenario stems describing a patient presentation, dive history, or wound status, followed by a request to identify the correct diagnostic step, treatment protocol, or hyperbaric indication. Understanding the outline's category weights is the single most efficient way to allocate study time, which is why we break down scheduling logic in the UHM Study Guide 2026: How to Pass on Your First Attempt.
The Four Content Domains
The official written-examination outline organizes content into four categories. Weighting is not evenly distributed, and candidates who study each domain proportionally to its weight tend to use their preparation time more efficiently than those who spread effort evenly across all four.
Domain 1: Fundamentals (40%)
This is the largest domain by a wide margin and covers the foundational science underlying hyperbaric and undersea medicine - physics and physiology principles, gas laws as applied to pressure environments, mechanisms of oxygen toxicity, and the physiologic basis for hyperbaric treatment.
- Expect the plurality of exam questions to originate here
- Underlying physiology concepts recur across other domains, so mastery here supports the rest of the exam
Domain 2: Diving medicine (30.5%)
Covers dive-related pathology and management - decompression illness, arterial gas embolism, barotrauma, and fitness-to-dive evaluation. Combined with Fundamentals, this domain accounts for the majority of the exam's weight.
- Diagnostic differentiation between decompression sickness types is a recurring theme
- Understanding dive tables and pressure-related injury mechanisms supports both this domain and Fundamentals
Domain 3: Clinical hyperbaric medicine (26.5%)
Focuses on the clinical application of hyperbaric oxygen therapy across its approved indications - wound care, necrotizing infections, carbon monoxide poisoning, radiation injury, and related treatment protocols.
- Indications map closely to the 13 treatment categories referenced in the case-log eligibility requirement
- Treatment protocol specifics (pressure, duration, table selection) are testable
Domain 4: Research (3%)
The smallest domain by weight, covering research literacy relevant to hyperbaric medicine practice - interpreting study design and evidence quality as it applies to treatment indications.
- Low weight means limited time investment relative to the other three domains
- Still worth reviewing basic evidence-hierarchy concepts once other domains are solid
For a section-by-section walkthrough of exactly what falls under each category, see UHM Exam Domains 2026: Complete Guide to All 4 Content Areas. And if you're trying to gauge realistically how much preparation this exam demands given its structure, How Hard Is the UHM Exam? Complete Difficulty Guide 2026 walks through the difficulty factors in detail.
| Domain | Weight | Focus |
|---|---|---|
| Fundamentals | 40% | Physics, physiology, gas laws, oxygen toxicity |
| Diving medicine | 30.5% | Decompression illness, barotrauma, dive fitness |
| Clinical hyperbaric medicine | 26.5% | HBOT indications, treatment protocols |
| Research | 3% | Evidence interpretation |
Fees and Recertification
The published examination fee and the recertification fee are each $1,100. Once certified, physicians maintain their status through the Osteopathic Continuous Certification (OCC) pathway, which includes a written recertification assessment within a 10-year cycle. Notably, the conjoint committee does not impose an additional UHM-specific CME requirement on top of this - candidates instead need to maintain their primary-board CME obligations, stay compliant with OCC, and keep an active, unrestricted medical license. This makes maintenance somewhat streamlined compared to credentials that layer subspecialty-specific CME on top of primary-board requirements.
For anyone budgeting for the full path - application, exam, and later recertification - UHM Certification Cost 2026: Complete Pricing Breakdown lays out the numbers in one place. And because scheduling text on the official page has occasionally carried over from prior cycles, it's worth cross-checking current administration windows against UHM Exam Dates 2026: Testing Windows, Deadlines & Scheduling before you commit to an application timeline.
Who Pursues UHM Certification
Because eligibility requires primary certification through AOBEM, AOBFP, AOBIM, or AOBPM, candidates for this subspecialty typically come from emergency medicine, family practice, internal medicine, or preventive medicine backgrounds within the osteopathic system. What draws them toward UHM certification is usually one of a few things: an interest in wound care and hyperbaric medicine centers, a role that includes diving medicine consultation, or a hospital-affiliated hyperbaric program that requires or prefers board-certified oversight physicians.
Employers hiring for hyperbaric medicine roles - hospital-based wound care centers, multi-specialty wound clinics, and military or occupational diving medicine programs - often list this certification as a differentiator, if not a requirement, for medical director or supervising physician positions. If you're evaluating whether this credential fits your career trajectory, UHM Jobs covers the kinds of positions that reference this certification, and UHM Salary Guide 2026: Complete Earnings Analysis discusses compensation considerations in more depth. For a broader cost-versus-benefit view, Is the UHM Certification Worth It? Complete ROI Analysis 2026 weighs the investment against the career upside.
How to Approach Your Preparation
Given the domain weighting, a practical preparation sequence starts with Fundamentals since it carries 40% of the exam and its physiology concepts underpin the other domains. From there, Diving medicine and Clinical hyperbaric medicine deserve roughly comparable attention given their similar weights (30.5% and 26.5%), while Research can be reviewed briefly near the end given its 3% weight.
Fundamentals
- Build a strong base in gas laws, physiology, and oxygen toxicity mechanisms since this domain carries the most weight
Diving medicine
- Work through decompression illness presentations, barotrauma patterns, and dive fitness evaluation criteria
Clinical hyperbaric medicine
- Review treatment protocols across the indications tied to the 13-category case-log requirement
Research and integration
- Cover research-literacy basics, then run mixed-domain practice questions to simulate the 150-question format
Whatever schedule you build, practicing with realistic multiple-choice scenarios matters more than passive review once you have foundational knowledge in place - you can work through domain-weighted practice questions at the main practice test site to get a feel for exam pacing and question style before your official test date. Pairing that with a structured review of the UHM Cheat Sheet 2026: One-Page Review of Must-Know Facts in your final week can help consolidate the highest-yield facts across all four domains.
Key Takeaway
Allocate study time roughly in proportion to domain weight - Fundamentals and Diving medicine together account for more than 70% of the exam, so they deserve the majority of your preparation hours.
If you want a broader look at how this certification compares to other credentials named "UHM" or general certification terminology, our related pages - UHM Certification, What Is UHM?, What Is UHM Certification?, What Does UHM Mean?, and UHM Training - each approach the topic from a different search angle while staying grounded in the same AOA-specific facts covered here. For a data-driven look at how candidates actually perform, UHM Pass Rate 2026: What the Data Shows is worth reading once you've reviewed the domain breakdown above. You can also start practicing right away at our practice test platform to benchmark where you stand before committing to a full study plan.
Frequently Asked Questions
No. This article covers specifically the AOA Subspecialty Certification in Undersea and Hyperbaric Medicine, administered through the American Osteopathic Conjoint Undersea & Hyperbaric Medicine Examination Committee. Other organizations use similar acronyms for different credentials with different requirements and fees, so always confirm which certifying body applies to your training pathway.
The written examination contains 150 multiple-choice questions distributed across four content domains: Fundamentals, Diving medicine, Clinical hyperbaric medicine, and Research.
You need a scaled score of at least 500 on a 200-800 scale. This is not a straightforward percentage-correct threshold, so review how scaled scoring works rather than estimating based on raw question counts.
Yes. Published eligibility requires completion of a one-year AOA- or ACGME-approved hyperbaric medicine fellowship, in addition to a COCA-accredited osteopathic medical degree, a one-year AOA-approved internship, and primary certification through AOBEM, AOBFP, AOBIM, or AOBPM.
No. The conjoint committee does not impose an additional UHM-specific CME requirement. Certified physicians maintain status by keeping current with primary-board CME, OCC compliance, and active unrestricted licensure, along with a written recertification assessment within each 10-year cycle.