What Is COHN Certification?

What COHN Certification Actually Is

COHN stands for Certified Occupational Health Nurse. It is a specialty credential for registered nurses whose practice centers on the health, safety, and well-being of working populations. Rather than testing general nursing knowledge, the certification evaluates whether you can apply nursing judgment inside an employment context: managing work-related injuries and illnesses, evaluating workplace hazards, supporting regulatory compliance, and running occupational health programs that serve an entire workforce.

That distinction matters if you are comparing credentials. This page is strictly about the nursing credential from ABOHN. If you are looking for broader background on the terminology, our explainers on what COHN is and what COHN stands for cover the naming in more detail, and the COHN certification overview gives a quick orientation.

Who Certifies It and How the Exam Is Delivered

The certification is administered by the American Board for Occupational Health Nurses, Inc. (ABOHN). The exam itself is delivered through Assessment Systems Corporation (ASC), which offers two delivery routes: in-person testing at a test center, or live remote proctoring through MonitorEDU. You choose the format that fits your circumstances when you schedule.

The exam is closed-book. You cannot bring reference materials, so preparation has to be about retention and application rather than knowing where to look something up. ABOHN publishes a candidate handbook (the current edition is dated March 2026), and it is the authoritative source for policies, content outlines, and procedures. Read it before you do anything else; it is the document your eligibility and testing experience will be judged against.

Eligibility: The 3,000-Hour Practice Requirement

The COHN is an experience-gated credential. You cannot sit for it straight out of nursing school. The core requirements are:

• An active RN license (or an international equivalent recognized under ABOHN's policies).
• 3,000 hours of occupational-health practice within the previous five years.

The handbook also describes specified education alternatives to the standard pathway, but these require approval from ABOHN. If you think you may qualify through an alternative route, contact the board and get that determination in writing before paying fees or planning a test date.

The hours requirement trips up more candidates than the exam content does. Occupational health duties are often blended into other roles: a nurse in an employee clinic who also handles disability management, or a nurse in a manufacturing plant who splits time between first aid and safety committee work. Document your hours by task, not by job title, because what counts is the nature of the work performed. Our detailed COHN requirements guide walks through how to think about qualifying hours and documentation.

Exam Format: 160 Questions, 135 Scored

The COHN exam consists of 160 multiple-choice questions administered over 3 hours. Of those, 135 are scored. The remaining 25 are pretest items that ABOHN is trialing for future exams. You will not know which are which, so every question deserves a full effort.

Three hours for 160 items gives you a little over a minute per question. That is workable for most candidates, but scenario-based items that describe a worker, a workplace, and a decision point take longer to read than a straight recall question. Practice reading efficiently: identify who the stem is asking you to act as, what the actual question is, and what constraints the scenario places on a safe, compliant response.

If you want a sense of how demanding the exam feels in practice, see how hard the COHN exam is.

The Three Content Domains

ABOHN organizes the exam into three domains. The official allocation of scored items is 72, 40, and 23 questions respectively, which together account for the 135 scored questions. Note that this is a count of items, not a set of percentage labels, so plan your preparation around the item counts.

For a deeper breakdown, read our complete guide to the COHN exam domains.

How Passing Is Determined

The COHN uses an Angoff-based passing standard, a criterion-referenced method in which subject-matter experts judge how a minimally competent candidate would perform on each item. In other words, you are measured against a defined competence standard, not ranked against other test-takers on a curve.

There is one point of caution on published statistics. ABOHN's certification statistics page reports a 65% figure for 2025 but also lists 57/85 in the same context, and that discrepancy is unresolved. Because of that, treat any single headline number with care and check the current ABOHN statistics page directly rather than relying on a secondhand figure. We break down what is and is not known in our COHN pass rate analysis and our COHN passing score guide.

Fees and Registration Mechanics

The process runs in two stages. First you apply to ABOHN and have your eligibility verified, including your RN license and practice hours. Once approved, you schedule your exam through ASC, choosing either a test center or live remote delivery via MonitorEDU. Build in time for application review so that a documentation question does not push you past your intended test window.

For a line-by-line view of what you will pay and what to budget beyond the exam itself, see our COHN certification cost breakdown, and check COHN exam dates and scheduling for timing considerations.

Where COHNs Work and Who Hires Them

Occupational health nurses work wherever employers have a stake in workforce health. Common settings include:

• Manufacturing and industrial sites, where injury management, hazard exposure, and surveillance programs are central.
• Corporate and employee health clinics, covering preventive care, wellness, and fitness-for-duty evaluations.
• Hospitals and health systems, which run employee health departments.
• Utilities, energy, construction, and transportation employers with safety-sensitive roles.
• Government agencies and the military-adjacent civilian workforce.
• Workers' compensation carriers, third-party administrators, and consulting firms, where case management skills are directly applicable.

The certification is most valuable when your role involves independent decision-making, case management, or program ownership. We explore the career angle in more depth in our COHN jobs overview, the COHN salary guide, and our analysis of whether the certification is worth it.

Sequencing Your Preparation Around the Domains

You do not need an elaborate method here, just a sequence that matches the exam's structure. Because Domain 1 holds 72 of the 135 scored items, give it the most calendar time and revisit it last. A sensible order follows the way the content builds.

Adjust the timeline to your own gaps. A nurse who handles OSHA recordkeeping daily may compress Domain 2, while someone from an acute-care background may need longer on compliance. Our COHN study guide expands on resources and pacing, and the COHN cheat sheet is useful for last-week review. When you are ready to test yourself under realistic conditions, try the COHN practice tests.

Keeping the Credential: Five-Year Recertification

Earning the COHN is not a one-time event. The credential runs on a five-year cycle, and recertification requires:

• Active RN status maintained throughout.
• 3,000 hours of practice in the recertification period.
• 50 related continuing nursing education (CNE) hours.

ABOHN also lists an annual maintenance/recertification fee of $150. Because policies and fee structures can change, confirm the current terms on the ABOHN recertification page before you plan your renewal. Selecting CNE that genuinely relates to occupational health, rather than generic continuing education, keeps your recertification straightforward and keeps your skills aligned with the three exam domains.

Frequently Asked Questions