CHRN Passing Score 2026: Exactly What You Need to Pass

The Passing Standard in Plain Terms

If you are searching for the Certified Hyperbaric Registered Nurse passing score, the answer is short: 70%. The current-linked June 2024 resource manual specifies a 120-question examination, a two-hour time limit, and a 70% passing threshold. The exam is built from multiple-choice and true/false items only; the manual explicitly excludes essays and short-answer questions.

That sounds simple, but a passing standard is only useful when you understand what it demands of your preparation. This article walks through what 70% means in practical terms, what is and is not publicly known about how the score is calculated, and how to allocate study time across the hyperbaric nursing content areas so the threshold is comfortably within reach. If you want the broader picture first, start with What Is CHRN Certification? and then return here.

What 70% of 120 Items Actually Requires

Taken at face value, 70% of 120 items is 84 correct answers. Treat that as a planning figure rather than an official raw cutoff, because the public documents do not say how many of the 120 items are scored versus unscored pretest items, and they do not say whether the threshold is applied to a raw count or a converted scale. If any items are unscored, the number of scored items would be lower than 120 and the required count would shift accordingly.

Two hours for 120 items leaves roughly one minute per question. That pace is comfortable for recall items but tight for calculation items, which is why the calculator and dive-table provisions matter (covered below).

Who Sets and Grades the Exam

Two bodies are involved, and keeping their roles straight prevents confusion about where to direct questions:

• Baromedical Nurses Association Certification Board (BNACB): oversees nursing eligibility and certification.
• National Board of Diving and Hyperbaric Medical Technology (NBDHMT): administers and grades the testing.

This split is worth remembering because the certification is a nursing credential governed by the nursing board, while the examination mechanics and scoring run through the NBDHMT. For the eligibility side of the process, see CHRN Requirements 2026: Eligibility, Prerequisites & How to Qualify.

Format, Time Limit, and Testing Conditions

Where and how you test

Testing takes place at a designated testing site. Any in-house proctorship requires NBDHMT approval. This is not default unproctored home testing, so plan around a proctored environment rather than assuming you can sit the exam anywhere.

What you may use

• A pocket calculator is allowed.
• Supplemental dive tables are provided at the exam.
• Unrestricted open-book testing is not established, so do not assume you can bring reference material.

What the Public Record Does Not Tell You

Responsible preparation means knowing where the published information stops. The following remain unverified in the sources available for this article:

• The scored/unscored item split within the 120 items.
• Whether the exam is adaptive.
• A complete current weighted blueprint and which content area carries the most weight.
• A CHRN-specific pass rate. A historical combined-program figure of 74% exists, but it is not specific to this certification and should not be quoted as the CHRN pass rate.

For a deeper treatment of that last point, see CHRN Pass Rate 2026: What the Data Shows. And because no official percentage weights are public, any claim that one content area is "worth" a specific share of the exam should be treated as unsupported. The practical response is balanced coverage with extra depth in areas that combine heavy content and calculation: physics, physiology, safety, and nursing management.

Where Your Points Come From: The Sixteen Preparation Topics

The June 2024 resource manual's study-guide contents list sixteen technical preparation topics. These are unweighted issuer study-guide competencies, not an authenticated official domain count, and the manual itself is inconsistent on section counts (thirteen detailed body sections against an introduction that still says twelve). Use them as your scope map. The full walkthrough is in CHRN Exam Domains 2026: Complete Guide to All 16 Content Areas; here is how they relate to scoring.

Note that the manual gives no separate detailed chapter bodies for the NFPA, BNA standards, and chamber-operation entries, and their full current external standards are not reproduced here. Plan to read those source standards directly rather than relying on a summary.

High-Yield Problem Types for Earning the Margin

Since you cannot know exact weights, concentrate on question types where preparation converts reliably into correct answers.

Calculation and table items

Practice pressure-unit conversions until the steps are automatic: converting between FSW, MSW, PSI, mmHg, and ATA, and distinguishing gauge from absolute pressure. Work gas-law scenarios (Boyle's for volume change with depth, Dalton's for partial pressures, Henry's for dissolved gas, Charles' for temperature effects) with a calculator in hand, since that matches testing conditions. Practice reading the Navy dive tables you will be provided, including repetitive group designation logic.

Scenario-based safety and nursing items

Patient-protection questions are rich in specifics: pre-treatment assessment requirements, restricted items (static-producing clothing, hairpieces, recently applied nail polish, make-up and body lotions, loose dentures, Velcro attachments, battery-operated devices such as hearing aids and Holter monitors), and special-risk populations including diabetic patients, patients with seizure history or recent head injury, febrile patients, those with chest surgery or penetrating chest injury, and those with a history of reconstructive ear surgery. Be ready to recognize signs of pulmonary barotrauma of ascent and premonitory signs of CNS oxygen toxicity.

Classification and recall items

Expect true/false and multiple-choice items that test whether you can match a mechanism to an indication, a toxicity type to its presentation, or a gas to its color code. These are efficiently learned with structured notes; our CHRN Cheat Sheet 2026: One-Page Review of Must-Know Facts is a useful compression of this material.

Registration, Fees, and Retakes

The June 2026 initial application confirms the fee structure and requires membership evidence for discounted tiers. It also states that you should register 30 days before the test.

The June 2024 manual lists US$100 for a repeat examination. No newer retake-fee override was found in the retrieved initial application, so confirm the current repeat fee with the NBDHMT before you pay. For the full cost picture, including renewal, read CHRN Certification Cost 2026: Complete Pricing Breakdown, and for scheduling logistics see CHRN Exam Dates 2026: Testing Windows, Deadlines & Scheduling.

The practical implication of the repeat-exam fee is that a first-attempt pass saves money, but the lower repeat fee also means a miss is recoverable. Either way, the stronger strategy is to sit the exam once you are scoring comfortably above the threshold on practice material.

Prerequisites Are Not Part of Your Score

A common point of confusion is mixing up the entry requirements with the exam clock. The 40-hour introductory course and 480 experience hours are prerequisites for sitting the exam; they are not the two-hour exam timer and they do not count toward your 70%. To qualify, candidates need:

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

Those prerequisites also shape the kind of nurse who hires into and benefits from the credential. Hyperbaric and wound-care programs in hospitals and outpatient clinics are the natural employers; explore CHRN Jobs, CHRN Salary Guide 2026: Complete Earnings Analysis, and Is the CHRN Certification Worth It? Complete ROI Analysis 2026 for the career side of the decision.

A Domain-Sequenced Plan Built Around the Threshold

Rather than a generic schedule, sequence your study so that concepts build on each other. Physics must come before physiology, physiology before decompression and oxygen toxicity, and all of that before safety and nursing management, because later topics lean on earlier ones. For a fuller approach, see CHRN Study Guide 2026: How to Pass on Your First Attempt.

After You Pass: Renewal Basics

Certification is not permanent. Renewal occurs every four years and, per the currently linked 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, and 40 CE hours over four years including 20 Category A hours. Renewal fees are US$150 (BNA), US$200 (UHMS or ACHM), and US$250 (nonmember); a lapse adds US$100 and removes member discounts. The newer form's employer-validated recent-practice requirement supersedes the older manual's statement that ongoing hours need not be logged.

If you are still orienting yourself to the credential, these primers cover the basics: What Is CHRN? and What Does CHRN Stand For? To gauge how demanding the exam is overall, see How Hard Is the CHRN Exam? Complete Difficulty Guide 2026.

When you are ready to test your readiness against exam-style questions, work through the full set of practice items on the CHRN Exam Prep practice test site and use the timed question sets to confirm you are clearing 70% with room to spare.

Frequently Asked Questions