- Who Controls the Calendar: BNACB and NBDHMT
- What We Can and Cannot Say About 2026 Dates
- Working Backward: The Pre-Application Timeline
- Registration Mechanics and Fees
- What You Are Scheduling: The Exam Itself
- Sequencing Your Prep Around the 16 Content Areas
- If You Need a Second Attempt
- After You Pass: The Four-Year Clock
- Frequently Asked Questions
- NBDHMT administers and grades the CHRN at designated testing sites; this is not default unproctored home testing.
- The June 2026 application says to register 30 days before the test, so treat that as your minimum lead time.
- Initial application fees are US$250 for BNA members, US$300 for UHMS/ACHM members and US$400 for nonmembers.
- Eligibility prerequisites, including 480 post-course patient-care hours, usually take longer than the exam window itself.
Who Controls the Calendar: BNACB and NBDHMT
Before you can plan around CHRN dates, you need to know which organization decides what. The Certified Hyperbaric Registered Nurse credential involves two bodies with distinct jobs. The Baromedical Nurses Association Certification Board (BNACB) oversees nursing eligibility and certification. The National Board of Diving and Hyperbaric Medical Technology (NBDHMT) administers and grades the examination at approved centers.
This split matters for scheduling. Your eligibility documents, including preceptor approval and employer recommendation, are the gate you must clear first. The testing logistics, meaning where you sit the exam and when, run through the NBDHMT administration process. If you are still orienting yourself on what the credential is, our explainer What Is CHRN Certification? covers the fundamentals, and CHRN Requirements 2026: Eligibility, Prerequisites & How to Qualify walks through qualification in depth.
What We Can and Cannot Say About 2026 Dates
Candidates searching for a neat list of 2026 test dates are often disappointed, and it is better to be upfront about why. The published materials we reviewed (the June 2026 initial application, the June 2024 Resource Manual, and the August 2025 renewal form) establish the rules of registration but do not give us a verified, fixed national calendar of CHRN sitting dates for 2026. We are not going to invent one.
What the official materials do establish is the mechanics around scheduling:
- Testing occurs at a designated testing site, and any in-house proctorship requires NBDHMT approval.
- The June 2026 initial application instructs applicants to register 30 days before the test.
- Membership evidence accompanies the application if you are claiming a member fee tier.
In practical terms, your "exam date" is something you confirm through the NBDHMT application process and your testing site rather than something you pick from a universal public calendar on this page. Check the NBDHMT nursing certification page for the current application and any listed testing information, then work backward from the date you secure.
Working Backward: The Pre-Application Timeline
For most candidates, the true bottleneck is not the exam window but the prerequisites. You cannot simply decide to test next month if your hours are not logged. The 40-hour entry course and the 480 experience hours are prerequisites, not part of the two-hour exam timer, and they dictate your earliest realistic sitting.
The eligibility components that gate your date
- Unrestricted RN license. Must be in good standing when you apply.
- Nursing experience. Two years in a hospital or clinic setting, or one year in critical care.
- Recent active hyperbaric year. Recent practice in the hyperbaric environment.
- Approved training. An approved 40-hour introductory course, or applicable 40 Category A replacement credits.
- 480 post-course patient-care hours. These count after you complete the introductory course, with qualified preceptor approval.
- Employer recommendation. Documentation from your workplace supporting your application.
The 480 post-course hours are the item most likely to push your timeline. They accrue only after the course, they require preceptor validation, and they depend on how many hyperbaric shifts your unit actually schedules you for. If you work part-time in a wound-care center that runs a few treatment days per week, the hours take longer than they would in a busy multiplace facility. If you are still in the training phase, our overview of CHRN Training is a useful companion.
Complete the 40-hour introductory course
- Confirm the course is approved, or confirm your Category A credits qualify as a replacement
- Keep your completion documentation in a single folder
Accrue 480 post-course patient-care hours
- Track hours contemporaneously with your preceptor
- Do not wait until the end to gather signatures
Assemble the application packet
- Employer recommendation and preceptor approval
- Membership proof if claiming a BNA or UHMS/ACHM rate
Register at least 30 days ahead
- Submit the application and fee per the June 2026 form
- Confirm your designated testing site and time
Registration Mechanics and Fees
The June 2026 initial application was retrieved and confirms three fee tiers tied to membership. Membership evidence is required for the discounted tiers, so plan for that paperwork in advance.
| Applicant Category | Initial Application Fee |
|---|---|
| BNA member | US$250 |
| UHMS or ACHM member | US$300 |
| Nonmember | US$400 |
Two scheduling-related fee points are worth noting. First, the June 2024 manual lists US$100 for a repeat examination, and no newer retake-fee override turned up in the retrieved initial application, so confirm the current retake amount with NBDHMT before you budget. Second, the gap between member and nonmember pricing is large enough that joining the relevant organization before applying may change your total outlay, though you should verify current membership dues and terms yourself. For the full financial picture, including course and renewal costs, see CHRN Certification Cost 2026: Complete Pricing Breakdown.
Key Takeaway
Treat the 30-day registration instruction as an absolute minimum, not a target. Submit earlier if you want flexibility in choosing a testing site and time, and so that any missing document can be corrected without costing you a window.
What You Are Scheduling: The Exam Itself
Knowing the format helps you choose a date that fits your preparation level. The June 2024 Resource Manual specifies the following:
- Length: 120 questions
- Item types: multiple-choice and true/false (essays and short-answer questions are explicitly excluded)
- Time limit: two hours
- Passing threshold: 70%
- Allowed aids: a pocket calculator is allowed, and supplemental dive tables are provided
- Setting: a designated testing site, not default unproctored home testing
The split between scored and unscored items has not been verified, and neither has whether the test is adaptive or open-book in any unrestricted sense, so do not assume either. Two hours for 120 items works out to roughly one minute per question, which makes calculation-heavy items on pressure conversion and gas laws a pacing consideration. Our guides on the CHRN passing score and how hard the CHRN exam is go deeper on what that 70% means in practice. On pass rates, the current CHRN-specific figure is not publicly disclosed, and a historical combined-program number should not be read as CHRN-specific; see CHRN Pass Rate 2026: What the Data Shows for how to interpret what is and is not known.
Sequencing Your Prep Around the 16 Content Areas
Once you have a confirmed date, the most useful thing you can do is allocate your weeks by content area rather than reading the manual front to back. The sixteen preparation categories come from the study-guide contents of the June 2024 Resource Manual. They are unweighted issuer competencies, and a current weighted blueprint has not been verified, so do not assume any domain is worth more than another. Instead, sequence by dependency: foundational physics and physiology first, because later topics lean on them. Our full breakdown is in CHRN Exam Domains 2026: Complete Guide to All 16 Content Areas.
Foundation block: Domains 1 through 3
History of Undersea and Hyperbaric Medicine; The Physical Aspects of Undersea and Hyperbaric Medicine; The Physiological Aspects of Undersea and Hyperbaric Medicine.
- Distinguish atmospheric, barometric, absolute, gauge and hydrostatic pressure
- Convert among ATA, FSW, PSI, MSW and mmHg
- Apply Dalton's, Henry's, Boyle's and Charles' Laws; convert Fahrenheit, Celsius, Rankine and Kelvin
- Know the historical contributors named in the objectives, including Behnke, Bert, Boyle, Brummelkamp, Fontaine, Haldane and others
Decompression and mechanisms block: Domains 4 and 5
Mechanisms and Theory of Decompression; Therapeutic Mechanisms Associated with Hyperbaric Oxygen Exposure.
- Working knowledge of the US Navy Standard Air Decompression Table, the No-Decompression Limits and Repetitive Group Designation Table, and the Residual Nitrogen Timetable
- Limits of those tables in preventing decompression sickness
- Six therapeutic mechanisms: antimicrobial effects, vasoconstriction, hyperoxygenation, neovascularization, attenuation of reperfusion injury, gas bubble reduction
Clinical and risk block: Domains 6, 7 and 8
Currently Accepted Indications; Oxygen Toxicity; Other Potential Complications.
- Know the UHMS currently accepted indications and the commonly used protocols for each (pressure, exposure time, frequency)
- Differentiate CNS oxygen toxicity (Paul Bert effect) from pulmonary oxygen toxicity (Lorrain Smith effect)
- Identify gas-filled spaces before compression and recognize airway compromise during decompression
Facility, safety and equipment block: Domains 9 through 12 and 16
The Hyperbaric Medicine Facility; Hyperbaric Safety I and II; NFPA guidelines; operation of monoplace and multiplace chambers.
- Chamber types, with advantages, disadvantages and operating characteristics
- Acrylic versus steel-hulled vessel design, compressed gas cylinder handling and gas color codes
- Fire-risk reduction and patient preparation: static-producing clothing, hairpieces, nail polish, lotions, loose dentures, hearing aids and Holter monitors
- Special risk groups, including diabetic patients, those with seizure history or recent head injury, febrile patients and those with prior chest or reconstructive ear surgery
Monitoring and nursing block: Domains 13 through 15
Transcutaneous Oxygen Monitoring; Nursing Management of the Patient Undergoing Hyperbaric Oxygen Therapy; Nursing Standards of Practice (BNA Hyperbaric Nursing Standards).
- TcPO2 technology, equipment inspection and obtaining consent for the procedure
- The nursing process, care planning, pharmacology in the hyperbaric hyperoxic environment, wound healing and adjunctive therapies
- Care of critically ill and pediatric patients
A note on source freshness: the June 2024 manual contains legacy clinical narrative, including a reference to a 1992 indications report as the most recent. That statement is outdated, since the public UHMS 15th-edition front matter is dated 2023. Use the manual to define scope, but verify clinical answers, accepted indications and safety standards against current authoritative sources. For a step-by-step approach, pair this with CHRN Study Guide 2026: How to Pass on Your First Attempt and the CHRN Cheat Sheet 2026 for final review.
One practical scheduling tie-in
If you have eight to ten weeks before your confirmed date, front-load the calculation domains. Pressure conversions and gas-law problems reward repetition, and you can practice them against the provided-dive-tables and pocket-calculator conditions you will face. Reserve the final two weeks for mixed-domain practice under a two-hour limit. You can run timed sets on our CHRN practice test platform.
If You Need a Second Attempt
Build a contingency into your calendar even if you expect to pass. The June 2024 manual lists US$100 for a repeat examination, though no newer figure was found, so verify before relying on it. Practically, a retake means another registration cycle, so remember the 30-day registration instruction and avoid scheduling your first attempt so close to a work deadline, a license renewal or a planned leave that a retake becomes impossible to fit.
If you do not pass, use your result to target weak domains rather than restarting from scratch. Our difficulty analysis in How Hard Is the CHRN Exam? discusses where candidates tend to struggle, and timed question sets on the main practice test site can help you rebuild accuracy quickly.
After You Pass: The Four-Year Clock
Planning your exam date also sets your first renewal date, so it is worth understanding the cycle now. Renewal runs every four years. The August 2025 renewal form requires:
- An active RN license
- Employer or medical-director confirmation of at least one year of hyperbaric experience, including 480 hours within the last 12 months
- 40 CE hours over four years, including 20 Category A hours
| Renewal Category | Renewal Fee |
|---|---|
| BNA member | US$150 |
| UHMS or ACHM member | US$200 |
| Nonmember | US$250 |
A lapse adds US$100 and removes member discounts. The older manual's statement that ongoing hours need not be logged does not waive the newer form's employer-validated recent-practice requirement, so start logging CE hours and practice hours from day one. If you are weighing the long-term value of the credential, see Is the CHRN Certification Worth It?, the CHRN Salary Guide and CHRN Jobs, which cover where certified hyperbaric nurses work and how the credential factors into hiring.
Frequently Asked Questions
The official materials we reviewed establish registration rules but not a verified national calendar of sitting dates. Confirm your testing site and time through the NBDHMT application process, and register at least 30 days before the test as the June 2026 application instructs.
The National Board of Diving and Hyperbaric Medical Technology (NBDHMT) administers and grades the exam at designated testing sites. The Baromedical Nurses Association Certification Board (BNACB) oversees nursing eligibility and certification.
Not by default. The exam is taken at a designated testing site, and any in-house proctorship requires NBDHMT approval. Unproctored home testing is not the standard arrangement.