- The NBDHMT Diver Medic Technician exam has 120 single-answer multiple-choice questions and a two-hour limit.
- Patient Assessment (25%) and Recompression Treatment & Decompression Procedures (22.5%) together make up nearly half the exam.
- Physics and Physiology (7.5%) and Chamber, Equipment and Operational Safety (5%) are small slices, but both are worth securing.
- A scientific calculator is permitted, so practice the pressure and gas-law math you will need.
The Diver Medic Technician Exam Blueprint at a Glance
- The Diver Medic Technician Exam Blueprint at a Glance
- Exam Format and Logistics
- How the Seven Domains Are Weighted
- Domain 3: Patient Assessment (25%)
- Domain 4: Recompression Treatment & Decompression Procedures (22.5%)
- Domain 2: DCS & CAGE (15%)
- Domain 6: Other Diving Related Injuries (15%)
- Domain 5: Invasive Procedures (10%)
- Domains 1 and 7: Physics, Physiology and Chamber Safety
- Sequencing Your Study Around the Weights
- What the Credential Does and Does Not Cover
- Frequently Asked Questions
Key Takeaways
- The NBDHMT Diver Medic Technician exam has 120 single-answer multiple-choice questions and a two-hour limit.
- Patient Assessment (25%) and Recompression Treatment & Decompression Procedures (22.5%) together make up nearly half the exam.
- Physics and Physiology (7.5%) and Chamber, Equipment and Operational Safety (5%) are small slices, but both are worth securing.
- A scientific calculator is permitted, so practice the pressure and gas-law math you will need.
- Initial certification costs USD 125, separate from provider training fees.
The Diver Medic Technician (DMT) credential, issued by the National Board of Diving and Hyperbaric Medical Technology (NBDHMT), tests a narrow, practical body of knowledge: how to recognize, assess, and treat diving injuries in the field, often far from a hospital. Unlike broad medical exams, its seven content areas are tightly tied to diving accidents and recompression chamber operations. Understanding how those areas are weighted is the single most useful step before you build a study plan.
This guide walks through all seven domains using the official category names and percentages, explains what each one expects of you, and shows how to sequence your preparation. If you are still deciding whether to pursue the credential, start with What Is DMT Certification? and DMT Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Exam Format and Logistics
The certification examination consists of 120 single-answer multiple-choice questions with a two-hour time limit. That works out to roughly one minute per question, which is comfortable for recall items but tighter for calculation-based or scenario-based questions. A scientific calculator is permitted.
Testing is administered online at Board-recognized testing centers, which include colleges and universities. The initial certification fee is USD 125, and that figure excludes whatever your approved training provider charges. For a full cost walkthrough, see DMT Certification Cost 2026: Complete Pricing Breakdown. Scheduling mechanics are covered in DMT Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
If you do not pass, the Certified Diver Medic Resource Guide specifies that a retest may be taken no sooner than three months after the first test. That gap is long enough that a failed attempt should trigger a targeted rebuild of your weakest domains rather than a quick repeat. A verified, current DMT-specific passing score or pass rate was not available in the issuer sources reviewed, so treat any figure you see elsewhere with caution. Our pages on the DMT passing score and DMT pass rate data explain what is and is not known.
How the Seven Domains Are Weighted
The official examination categories and their shares of questions are shown below. The question counts follow directly from the percentages applied to a 120-question exam.
| Domain | Share of Exam | Approx. Questions |
|---|---|---|
| 1. Physics and Physiology | 7.5% | 9 |
| 2. Decompression Sickness & Cerebral Arterial Gas Embolism | 15% | 18 |
| 3. Patient Assessment | 25% | 30 |
| 4. Recompression Treatment & Decompression Procedures | 22.5% | 27 |
| 5. Invasive Procedures | 10% | 12 |
| 6. Other Diving Related Injuries, Side Effects & Complications | 15% | 18 |
| 7. Chamber, Equipment and Operational Safety | 5% | 6 |
Notice the shape of the blueprint. Domains 3 and 4 account for 47.5% of the exam, or 57 of 120 questions. Add Domains 2 and 6 and you have covered 77.5%. This is an exam where clinical judgment about injured divers dominates, and where the foundational science and equipment topics, while essential, carry less weight.
Domain 3: Patient Assessment (25%)
Patient Assessment is the largest domain, with about 30 questions. For a diver medic, assessment is the core professional skill: you are often the only medically trained person present, and the decisions that follow depend on what you find.
Patient Assessment
Expect scenario-driven questions that ask what you would evaluate, in what order, and what the findings imply.
- Primary and secondary survey logic applied to a diving casualty
- Neurological examination findings and how to interpret changes over time
- Gathering dive history: depth, time, gas, ascent profile, and symptom onset
- Recognizing which presentations demand immediate escalation
- Documentation and communication with a supervising physician
Because this domain rewards pattern recognition, work through realistic casualty scenarios rather than memorizing lists. The neurological exam is a particularly high-value skill, since it underpins the diagnosis and tracking of the conditions in Domain 2. You can test your scenario reasoning with the question sets on the main practice test site.
Domain 4: Recompression Treatment & Decompression Procedures (22.5%)
The second-largest domain, worth roughly 27 questions, covers the treatment itself. This is where the diver medic role becomes distinctive: you may be operating or assisting with a chamber to treat a diving injury.
Recompression Treatment & Decompression Procedures
Questions here connect diagnosis to action, so you must know which treatment approach fits which presentation.
- Standard recompression treatment tables and when each is selected
- Pressure, depth, and time elements of treatment profiles
- Oxygen use during treatment and the monitoring it requires
- Decompression procedures and ascent management
- Responding when a patient fails to improve or deteriorates in the chamber
Expect to read a patient's status and choose the next step. This domain often involves arithmetic, which is why the permitted scientific calculator matters. Practice working treatment-profile timing and pressure conversions until they are automatic. Our DMT Cheat Sheet 2026 collects the quick-reference facts that are easy to forget under time pressure.
Domain 2: Decompression Sickness & Cerebral Arterial Gas Embolism (15%)
This domain, about 18 questions, covers the two signature diving injuries. Domain 2 supplies the disease knowledge, while Domains 3 and 4 supply the assessment and treatment skills built around it.
DCS and CAGE
Know the mechanisms, the presentations, and what distinguishes the two conditions.
- How inert gas forms bubbles during or after ascent
- Typical signs and symptoms, and how quickly they tend to appear
- Differentiating DCS from arterial gas embolism in the field
- Risk factors, including dive profile and ascent circumstances
- Why early recognition and recompression matter
A reliable approach is to study DCS and CAGE side by side, using a table of mechanism, onset, presentation, and first response. Many wrong answers on this domain come from confusing the two. For general background on the role these conditions create, see What Is DMT?.
Domain 6: Other Diving Related Injuries, Side Effects & Complications (15%)
Also carrying about 18 questions, this domain is a broad catch-all that rewards breadth. It covers the injuries and complications that occur around diving and recompression beyond DCS and CAGE.
Other Diving Related Injuries
Think of this as everything that can go wrong with a diver or a treatment besides the two headline conditions.
- Barotrauma affecting the ears, sinuses, lungs, and other air-containing spaces
- Gas toxicity and related effects on the body
- Marine-life injuries and environmental exposure problems
- Side effects and complications of oxygen therapy and recompression
- Conditions that can mimic or complicate a diving injury
Because the topic list is wide, use a one-line summary card for each condition: cause, signs, immediate management, and what to report to the physician. Breadth beats depth here.
Domain 5: Invasive Procedures (10%)
Invasive Procedures accounts for about 12 questions. These are skills a diver medic may perform only within the limits of training and authorization, and the exam tests both the technique and the judgment behind it.
Invasive Procedures
Know the indications, the steps, and the risks, plus the chamber-specific considerations.
- Establishing and managing intravenous access
- Airway management techniques and adjuncts
- Procedures that must be adapted for use inside a pressurized chamber
- Complications to watch for and how to respond
- When medical orders or physician contact are required before proceeding
Your practical training covers hands-on technique, but the exam tests the reasoning behind it. For more on how training maps to the test, read DMT Training.
Domains 1 and 7: Physics, Physiology and Chamber Safety
These two domains total just 12.5% of the exam, about 15 questions between them, but they are among the most dependable places to earn points because the material is stable and answerable.
Domain 1: Physics and Physiology (7.5%)
Roughly nine questions cover the gas laws and how pressure affects the body. This is the conceptual foundation for everything else, since understanding why bubbles form and why gases behave as they do makes Domains 2 and 4 far easier.
- Pressure, depth, and volume relationships and the gas laws that describe them
- Partial pressure concepts and their physiological consequences
- Respiratory and circulatory basics as they relate to diving
- Calculations you can complete with a scientific calculator
Domain 7: Chamber, Equipment and Operational Safety (5%)
Only about six questions, but the topics are concrete and learnable. They cover the safe operation of the chamber and its support equipment.
- Chamber components and pre-operation checks
- Gas supply, oxygen handling, and fire-safety precautions
- Communication and monitoring during treatment
- Emergency procedures for equipment problems
Key Takeaway
Do not skip the small domains. At 7.5% and 5%, they are quick to master compared with the clinical domains, and every question you secure here reduces the pressure on Patient Assessment and Recompression Treatment.
Sequencing Your Study Around the Weights
A good plan follows the blueprint rather than your comfort zone. The outline below ties each week to the domains that most reward early attention. For a fuller plan, see the DMT Study Guide 2026: How to Pass on Your First Attempt.
Foundations First
- Domain 1: gas laws, partial pressures, and the calculations you will do with a calculator
- Domain 7: chamber components, oxygen handling, and safety checks
The Disease Picture
- Domain 2: DCS and CAGE mechanisms, onset, and presentation side by side
- Domain 6: one summary card per injury or complication
The Heavy Hitters
- Domain 3: neurological exam and scenario-based assessment drills
- Domain 4: treatment-profile logic and timing calculations
Integration and Timing
- Domain 5: indications, steps, and scope-of-practice boundaries
- Full 120-question timed sets, reviewing every miss by domain
Foundations come first because Physics and Physiology explains the clinical material that follows. The heaviest clinical domains then get your freshest attention in the third week, and the final week is for timed practice. Run full-length sets under the two-hour limit so the pacing of 120 questions feels familiar. If the workload feels daunting, How Hard Is the DMT Exam? puts the difficulty in context.
What the Credential Does and Does Not Cover
It helps to know what you are preparing for. The DMT is built for field diving-accident response, and the Use Agreement is explicit that this credential alone does not qualify its holder for general clinical hyperbaric employment without further training, except to assist in treating an injured diver. That distinction shapes the exam: it emphasizes diving injuries and recompression rather than the full range of hyperbaric medicine.
The prerequisites are real, too. They include Board-approved DMT training, current accepted emergency-medicine documentation, medical clearance for a pressurized chamber setting, an instructor evaluation, a completed application, and the DMT Use Agreement. Accepted emergency-medicine documentation includes a DOT/NHTSA-approved course certificate, a current National Registry EMT or paramedic certification, or current state EMT licensure or certification. Chamber medical fitness does not itself require clearance to dive. Details are in DMT Requirements 2026.
Certification is not permanent. Renewal is required every two years and involves continuing education and observation requirements, plus a renewal fee of USD 75. Letting the credential lapse for more than a year means a new application and a new certification exam, so factor renewal into your long-term plan. If you are weighing the investment, see Is the DMT Certification Worth It?, and explore career paths in DMT Jobs and the DMT Salary Guide 2026.
Frequently Asked Questions
Patient Assessment is the largest at 25%, about 30 of 120 questions. Recompression Treatment & Decompression Procedures follows at 22.5%, about 27 questions. Together they make up nearly half the exam.
The exam has 120 single-answer multiple-choice questions with a two-hour time limit. A scientific calculator is permitted, which matters for gas-law and treatment-profile math.
Yes. The Certified Diver Medic Resource Guide specifies that a retest must be taken no sooner than three months after the first test. Use that interval to rebuild your weakest domains.
No. The two-hour limit applies to the written certification test. Practical clinical skills are taught separately as part of Board-approved training.
The initial certification fee is USD 125, as listed on the Diver Medic Certification Form. It excludes provider training costs, which are set by the approved training provider.
With the weights clear and a plan built around them, the next step is practice under realistic conditions. Take timed question sets on the DMT Exam Prep practice test site and review every miss by domain so your remaining study time goes where the exam rewards it most.