CHRN Pass Rate 2026: What the Data Shows

What "Pass Rate" Means for the Certified Hyperbaric Registered Nurse Exam

Nurses researching the Certified Hyperbaric Registered Nurse credential often start with the same question: what percentage of candidates pass? It is a reasonable instinct. A pass rate feels like a shortcut to understanding difficulty. For this credential, however, the honest answer is that the data is thin, and anyone quoting a precise current figure is either guessing or borrowing a number from somewhere else.

This article lays out what is actually known about outcomes for the CHRN, what the published exam structure implies about difficulty, and how to use that structure to prepare. If you want the broader difficulty picture, our guide on how hard the CHRN exam is pairs well with this one, and the dedicated CHRN pass rate page tracks the same topic from a different angle.

What Is (and Isn't) Published

The nursing certification is governed by the Baromedical Nurses Association Certification Board (BNACB), while the National Board of Diving and Hyperbaric Medicine Technology (NBDHMT) administers and grades the examination at approved testing centers. Neither body, in the materials reviewed for this article, publishes a current credential-specific pass rate for the Certified Hyperbaric Registered Nurse exam.

There is a historical combined-program figure of 74% that circulates in discussions of hyperbaric certification. That number is not CHRN-specific. It reflects a blended picture across programs, and it would be a mistake to treat it as the probability that a hyperbaric nurse passes on a given attempt. Hyperbaric nursing candidates are also a self-selected group: they have already completed a 40-hour course, logged hundreds of supervised patient-care hours, and secured employer and preceptor sign-off.

Why a Single Percentage Would Mislead You

Even if a current figure existed, it would tell you less than you might hope. Pass rates blend very different candidate groups: first-time testers and repeat testers, nurses with years of hyperbaric experience and those who just crossed the 480-hour line, people who studied the full manual and people who relied on their clinic's daily routine. The number that matters to you is your own readiness against the published scope.

A more useful approach is to ask what the exam rewards. The structure points to a test that rewards breadth across physics, physiology, safety, and nursing management rather than deep specialization in any one area. A nurse who is excellent at wound care but shaky on gas laws and chamber fire prevention is the profile most likely to struggle. Our CHRN study guide walks through how to close those gaps.

Exam Mechanics That Shape Outcomes

The June 2024 Resource Manual specifies the format clearly, and the format itself influences how candidates perform.

• Length and time: 120 questions in two hours, which works out to roughly one minute per item.
• Item types: multiple-choice and true/false. Essays and short-answer questions are explicitly excluded.
• Passing threshold: 70%.
• Reference materials: supplemental dive tables are provided, and a pocket calculator is allowed.
• Testing environment: a designated testing site. Any in-house proctorship requires NBDHMT approval, so this is not default unproctored home testing.

What remains unverified is also worth knowing. The split between scored and unscored items is not established, and the full current weighted blueprint is not confirmed. That means you cannot reliably calculate how many questions you can miss from the 70% figure alone, since you do not know whether every one of the 120 items counts. For a deeper look at the cut score, see our explainer on the CHRN passing score.

Prerequisites Act as a Filter Before You Ever Test

One reason raw pass rates are hard to interpret is that the Certified Hyperbaric Registered Nurse pathway screens candidates heavily before exam day. To be eligible, you need:

• An unrestricted RN license.
• Two years of hospital or clinic experience, or one year of critical care.
• A recent, active year of hyperbaric experience.
• An approved 40-hour introductory course, or applicable 40 Category A replacement credits.
• 480 post-course direct patient-care hours, with qualified preceptor approval and an employer recommendation.

It is worth stating plainly that the 40-hour course and the 480 experience hours are prerequisites, not part of the two-hour exam timer. By the time a nurse registers, they have already demonstrated sustained clinical exposure. The full eligibility picture is in our CHRN requirements guide.

The initial application says to register 30 days before the test. Missing that window can push your attempt back, so check CHRN exam dates and scheduling details early rather than assuming you can sit on short notice.

The Content Areas Where Candidates Most Often Lose Points

The manual's study-guide contents organize preparation into sixteen topic areas, listed below as the content domains for this credential. These are unweighted issuer study-guide competencies; the official percentage weights are not verified, so the grouping below is editorial emphasis, not an official blueprint. The full list lives in our CHRN exam domains guide.

A caution on sources: the manual's own list of sixteen preparation topics, thirteen detailed body sections, and an introduction that still says twelve sections should not be read as an authenticated domain count. Use it to establish scope, then verify clinical answers, accepted indications, and safety standards against current authoritative references such as the 2023 UHMS indications front matter. The manual contains legacy clinical narrative, including a reference to a 1992 report as the most recent, which is outdated.

The Calculation Skills You Can Bank in Advance

Because dive tables are provided and a calculator is allowed, calculation items are among the most controllable points on the exam. The skill is not memorizing numbers; it is knowing which law applies and how to set the problem up cleanly.

1. Pressure conversions: practice moving among ATA, FSW, MSW, PSI, and mmHg until the setup is automatic.
2. Gas laws: match the scenario to Boyle's (volume and pressure), Charles' (volume and temperature), Dalton's (partial pressures), or Henry's (dissolved gas). Misidentifying the law is the usual error.
3. Temperature conversion: remember that Rankine and Kelvin are absolute scales and are the ones used in gas law work.
4. Table navigation: practice reading the Navy tables so you can locate the correct row and repetitive group quickly under time pressure.

Sequencing Your Prep Around the Domains

Rather than a generic schedule, order your preparation by dependency: physics and physiology first, because mechanisms, toxicity, and safety all build on them. This is one possible sequence; adjust it to your own weak spots.

After you finish a pass through the domains, shift toward timed practice so the one-minute-per-item pace feels normal. You can drill that format with our practice questions on the main practice test site, and our CHRN cheat sheet is useful for last-day review of high-yield facts.

Fees, Retakes, and What a Miss Costs

Since no reliable pass rate exists, plan as though a first-attempt pass is your goal but understand the financial stakes. The June 2026 initial application confirms the following exam fees, with membership evidence required:

The June 2024 manual lists US$100 for a repeat examination, and no newer retake-fee override was found in the retrieved initial application, so confirm the current repeat fee with NBDHMT before you rely on that figure. For the complete cost picture, including renewal, see our CHRN certification cost breakdown.

Passing is not the end of the obligation. Certification renews every four years and requires an active RN license, 40 continuing education hours including 20 Category A, and recent-practice validation including 480 hours in the previous 12 months. The August 2025 renewal form lists fees of US$150 for BNA members, US$200 for UHMS or ACHM members, and US$250 for nonmembers; a lapse adds US$100 and removes member discounts. If you are weighing whether the effort pays off, our ROI analysis and salary guide cover that side of the decision.

Frequently Asked Questions

If you are still deciding whether this path fits you, start with what CHRN certification is and the typical roles described in our CHRN jobs overview, then work through the domain guide above and test yourself on the practice exam.