- What This Cheat Sheet Covers (and What It Doesn't)
- Exam Format at a Glance
- The Seven-Domain Blueprint
- Must-Know Facts by Domain
- Eligibility, Fees, and Retest Rules
- Two-Year Renewal Rules
- Scope of Practice: What the Credential Does and Doesn't Cover
- Scheduling Domains Across Your Final Weeks
- Frequently Asked Questions
- The Diver Medic Technician exam has 120 single-answer multiple-choice questions with a two-hour limit.
- Patient Assessment (25%) and Recompression Treatment & Decompression Procedures (22.5%) together make up nearly half the exam.
- Initial certification costs USD 125; renewal is USD 75 every two years, plus USD 50 if renewed within one year after expiry.
- A scientific calculator is permitted, so practice physics and pressure calculations with one.
What This Cheat Sheet Covers (and What It Doesn't)
This page condenses the Diver Medic Technician (DMT) credential, issued and examined by the National Board of Diving and Hyperbaric Medical Technology (NBDHMT), into a single scannable review. It is built for the final stretch of preparation: the week before your test, the night before your chamber-skills evaluation, or the moment you need to double-check a fee or a renewal deadline.
Use it as a map, not a substitute for training. The DMT is a field-diving-accident credential, and the exam tests whether you can assess an injured diver, recognize decompression illness, support recompression treatment, and operate safely around a chamber. If you are earlier in your journey, start with the overview of DMT certification or the full DMT study guide, then return here to lock in the facts.
Exam Format at a Glance
| Item | Detail |
|---|---|
| Administering body | National Board of Diving and Hyperbaric Medical Technology (NBDHMT) |
| Number of questions | 120 |
| Question style | Single-answer multiple choice |
| Time limit | Two hours |
| Calculator | Scientific calculator permitted |
| Delivery | Online, at Board-recognized testing centers (including colleges and universities) |
| Initial certification fee | USD 125 (excludes provider training) |
| Retest | No sooner than three months from the first test |
What the format means for pacing
Two hours for 120 questions works out to an average of one minute per question. That is comfortable for recall items (a symptom, a definition, a contraindication) but tight for items that require a calculation or a multi-step treatment-table decision. Plan to move quickly through the knowledge-recall questions so you bank time for the problems that need your calculator.
The two-hour limit applies to the certification test only. Practical clinical skills are handled separately, as part of Board-approved training. For more on how demanding the written test feels in practice, see how hard the DMT exam really is.
The Seven-Domain Blueprint
The NBDHMT examination guidelines divide the test into seven official categories. The question counts below follow the 120-question exam and match the published percentages.
| Domain | Weight | 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 |
For a deeper walkthrough of each content area, read the complete guide to all seven DMT exam domains.
Must-Know Facts by Domain
The Board's approved training course outline supplements the examination categories, but it includes introductory teaching material that is not tested and has some internal numbering inconsistencies. Treat the seven-domain blueprint above as your authority for what the exam measures, and use the course outline to deepen your understanding of each topic.
Domain 1: Physics and Physiology (7.5%, 9 questions)
Small in weight, but it underpins everything else. These questions reward comfort with pressure and gas behavior, which is where your scientific calculator earns its place.
- Pressure, depth, and gas-law relationships as they apply to divers and chamber work
- How gases behave in tissues under pressure and during ascent
- Basic respiratory and circulatory physiology relevant to diving injury
- Practice setting up and solving pressure calculations quickly and accurately
Domain 2: Decompression Sickness & Cerebral Arterial Gas Embolism (15%, 18 questions)
The core diagnostic content of the credential. Expect questions that ask you to distinguish presentations and recognize which condition a diver's story and symptoms point toward.
- Mechanisms and typical presentations of decompression sickness
- Mechanisms and typical presentations of cerebral arterial gas embolism
- How the dive profile, ascent events, and symptom onset help separate the two
- Why prompt recognition and treatment matter to outcomes
Domain 3: Patient Assessment (25%, 30 questions)
The single largest domain. This is where field-diving-accident competence is tested most heavily, and it is the domain where careful reading of the question stem pays off.
- Systematic history-taking, including the dive history and the sequence of symptoms
- Neurological examination findings and what changes in them mean over time
- Vital signs, primary and secondary assessment, and ongoing reassessment
- Recognizing when a presentation is serious enough to change priorities
Domain 4: Recompression Treatment & Decompression Procedures (22.5%, 27 questions)
The second-largest domain and the most procedural. Questions test whether you understand how treatment decisions are made and carried out, not just what the treatments are called.
- Treatment-table logic: when a given approach is used and how responses guide next steps
- Decompression procedures and the reasoning behind them
- Tending a patient during recompression, including monitoring and intervention
- Calculation and timing questions that benefit from your calculator
Domain 5: Invasive Procedures (10%, 12 questions)
Hands-on interventions that a diver medic may perform within the limits of orders and the scope of practice described in the DMT Use Agreement.
- Indications and contraindications for each procedure
- Basic technique, complications, and how to recognize them
- The role of medical orders or physician contact for advanced life support
Domain 6: Other Diving Related Injuries, Side Effects & Complications (15%, 18 questions)
Everything that is not DCS or arterial gas embolism but still shows up around diving and recompression.
- Barotrauma and other pressure-related injuries
- Side effects and complications that can arise during treatment
- Recognizing and responding to problems that develop in the chamber
Domain 7: Chamber, Equipment and Operational Safety (5%, 6 questions)
Only six questions, but they are often the most straightforward points on the exam if you have spent time around a chamber.
- Safe operation practices and awareness of chamber hazards
- Equipment familiarity and operational checks
- Fire and oxygen-safety awareness in a pressurized environment
Eligibility, Fees, and Retest Rules
The Certified Diver Medic Resource Guide lists the prerequisites for sitting the examination. Confirm each one before you pay, because gaps here delay testing more often than a missed fact on the exam.
- Board-approved DMT training completed with an approved provider.
- Current, accepted emergency-medicine documentation: a DOT/NHTSA-approved course certificate, current National Registry EMT or paramedic certification, or current state EMT licensure or certification.
- Medical clearance for a pressurized chamber setting. This is a chamber fitness requirement and does not itself require clearance to dive.
- An instructor evaluation.
- A completed application and a signed DMT Use Agreement.
For a full pricing picture, including how training costs fit around the exam fee, see the DMT certification cost breakdown. For a closer look at each prerequisite and how to document it, read DMT requirements and eligibility, and for scheduling logistics see DMT exam dates, testing windows, and deadlines.
Two-Year Renewal Rules
Certification must be renewed every two years. The renewal rules are detailed enough that candidates often get them wrong, so this section is worth memorizing alongside the exam content.
What the resource guide requires
- 24 additional training hours, broken down as at least four in diving medicine, at least sixteen in general or emergency medicine at EMT level or higher, and four further related hours.
- At least 24 hours of ambulance or emergency-room observation. Supervisor-attested offshore cases can satisfy the observation requirement.
The guide's checklist and the currently linked Certified Diver Medic Recertification Form label the education requirement as "24 CEUs." Keep the guide's hours terminology in mind when you log your training, and do not assume the CEU label means a different quantity of study than the 24 hours the guide describes.
What the recertification form adds
- Medical clearance
- Current EMT-or-higher documentation
- 24 hours of diving medicine or other emergency-related experience
- In its Military/Federal Requirements section, four actual or simulated DCI cases as inside tender or chamber operator in each two-year cycle
| Renewal Situation | Cost / Consequence |
|---|---|
| On-time renewal | USD 75 |
| Renewal within one year after expiry | USD 75 plus an additional USD 50 |
| Lapse exceeding one year | New application and new certification exam required |
Key Takeaway
Start logging training hours and observation shifts at the beginning of your two-year cycle, not the end. A lapse of more than one year means going back through the application and the full exam, which makes late renewal far more expensive than the USD 50 late fee suggests.
Scope of Practice: What the Credential Does and Doesn't Cover
The DMT Use Agreement defines how a certified diver medic may work. Two points matter for both the exam and your career planning.
- Advanced life support is conditional. It requires the medical orders or physician contact specified in the Use Agreement.
- The credential has a defined purpose. It is a field-diving-accident certification. By itself it does not qualify its holder for general clinical hyperbaric employment without further training, except to assist in treating an injured diver.
If you are weighing the credential against your career goals, the overview of DMT jobs describes the kinds of settings where diver medics work, the DMT salary guide covers earnings, and the ROI analysis helps you decide whether the investment fits your path.
Scheduling Domains Across Your Final Weeks
Methodology matters less than allocation. The plan below spends your time in proportion to the blueprint weights while front-loading the foundational material that makes the heavier domains easier.
Foundations and Diagnosis
- Domain 1: pressure and gas relationships, with calculator drills
- Domain 2: compare DCS and arterial gas embolism presentations side by side
The Heavy Hitters
- Domain 3: assessment sequences and neurological findings
- Domain 4: treatment-table logic and tending decisions
Procedures and Complications
- Domain 5: indications, contraindications, and complications
- Domain 6: barotrauma and treatment-related complications
- Domain 7: chamber and oxygen-safety review
Timed Practice
- Full-length 120-question sets under a two-hour limit
- Review misses by domain and revisit Domains 3 and 4 first
Finish with timed sets on the DMT practice test so the one-minute-per-question pace feels routine, and use the practice question bank to find the domains where your accuracy lags.
Frequently Asked Questions
The exam has 120 single-answer multiple-choice questions with a two-hour time limit. A scientific calculator is permitted.
Patient Assessment is the largest at 25% (30 questions), followed by Recompression Treatment & Decompression Procedures at 22.5% (27 questions). Together they account for 57 of the 120 questions.
A current DMT-specific passing score was not verified in the issuer sources reviewed for this article, so confirm it directly with the NBDHMT. For more context, see our page on the DMT passing score and the discussion of what pass-rate data does and does not show.
Initial certification is USD 125, excluding provider training. Renewal is USD 75 every two years, with an additional USD 50 if you renew within one year after expiry. A lapse longer than one year requires a new application and the certification exam.
The resource guide specifies no sooner than three months from the first test. Use that window to rebuild weak domains, starting with Patient Assessment and Recompression Treatment, since they carry the most questions.