1.1 COHN Exam Format & ABOHN Certification Eligibility
Key Takeaways
- ABOHN, established in 1972, is the sole certifying body for occupational health nurses in the United States, and COHN eligibility requires a current RN license (or international equivalent) plus 3,000 hours of occupational health nursing work experience earned in the previous 5 years.
- The COHN exam is 160 computer-based multiple-choice items (135 scored + 25 pretest) delivered in 3 hours by Assessment Systems Corporation at test centers or by live remote proctoring.
- Fees are a $150 application fee and a $400 examination fee, with an optional one-time $50 extension that adds 60 days to the 120-day testing authorization.
- The passing point is set by the Angoff method; the score report gives pass/fail plus raw scores by major content category, and ABOHN emails results within 2 weeks.
- Maintaining Active status requires an annual renewal application and fee plus 5-year recertification with 50 occupational-health CNE hours and 3,000 practice hours.
1.1 COHN Exam Format & ABOHN Certification Eligibility
Quick Summary: The Certified Occupational Health Nurse (COHN) credential is administered by the American Board for Occupational Health Nurses (ABOHN). To qualify, candidates must hold a current RN license and document at least 3,000 hours of occupational health nursing work experience within the previous 5 years. The exam consists of 160 multiple-choice questions (135 scored, 25 pretest) delivered in 3 hours. The passing point is established by the Angoff method, score reports give pass/fail plus raw scores by major content category, and credential holders renew annually and recertify every 5 years.
ABOHN Governance & Professional Credentialing
The American Board for Occupational Health Nurses, Inc. (ABOHN) was established as an independent nursing specialty certification board in 1972. It is the sole certifying body for occupational health nurses in the United States, and its certification programs are accredited by the National Commission for Certifying Agencies (NCCA), the accrediting arm of the Institute for Credentialing Excellence (ICE).
ABOHN awards three credentials: Certified Occupational Health Nurse (COHN), Certified Occupational Health Nurse – Specialist (COHN-S), and Case Management (CM). COHN and COHN-S are the two core credentials, and you may hold only one of them at a time. CM is an add-on that requires an active COHN or COHN-S plus 10 case-management contact hours earned in the previous 5 years.
The COHN examination focuses on the OHN clinician practice; the COHN-S examination places greater emphasis on administration in the workplace. ABOHN's own guidance is emphatic on this point: choose the examination that fits your practice, not your level of education.
| Credential Feature | Certified Occupational Health Nurse (COHN) | Certified Occupational Health Nurse – Specialist (COHN-S) |
|---|---|---|
| Licensure Prerequisite | Current RN license or international equivalent | Current RN license or international equivalent |
| Education Prerequisite | None beyond RN licensure (ADN, diploma, or BSN all qualify) | Bachelor's degree or higher — it does not need to be in nursing |
| Practice Experience | 3,000 hours of OHN work experience in the previous 5 years | 3,000 hours of OHN work experience in the previous 5 years |
| Practice Emphasis | Clinician practice: direct clinical care, case management, coordination | Broader management, education, and consultation role in the workplace |
| Largest Blueprint Domain | Clinical Practice & Case Management — 72 of 135 scored items (53.3%) | Clinical Practice & Case Management — 45 of 135 scored items (33.3%) |
| Exam Length | 160 items / 3 hours | 160 items / 3 hours |
Exam Trap Warning: A very common misconception is that COHN-S requires a BSN. It does not. ABOHN requires a bachelor's degree or higher in any field. Conversely, a BSN does not disqualify you from the COHN — an ADN-prepared nurse and a BSN-prepared nurse are equally eligible for COHN.
Eligibility Prerequisites & Education Alternatives to Work Hours
To sit for the COHN examination, a candidate must satisfy two mandatory requirements:
- Current RN Licensure: A current registered nurse license, or an international equivalent. ABOHN's rationale is simply proof that the candidate is a registered nurse.
- Practice Hour Requirement: 3,000 hours of occupational health nursing work experience earned during the five years prior to application. "Work experience" means actively engaged in occupational health nursing for compensation. 3,000 hours is roughly 1.5 years of full-time work (40 hours per week for 75 weeks).
ABOHN also allows academic time to substitute for a portion of the work-hour requirement, but with hard caps and hard conditions:
| Alternative Pathway | Maximum Work-Hour Credit | Conditions |
|---|---|---|
| Master's, PhD, or DNP dedicated to Occupational and Environmental Health and Safety (OEHS) | 3,000 hours | Program must include a semester/quarter of practical experience and an occupational-health-related project |
| Bachelor's or certificate program dedicated to OEHS | 2,000 hours | Basic industry content with limited or no practical experience; treated as equivalent to one year of graduate study |
Three conditions apply to both pathways: the degree must be completed within the five-year period prior to application; a transcript must be submitted with the application; and time spent in degree-granting programs before becoming an RN cannot be counted. Programs not already on ABOHN's accepted list must be approved by the committee before you submit your application.
Applications are submitted online with a copy of the RN license, a copy of the job description, and the application fee. Processing takes up to two weeks, and all applications are subject to audit and verification.
Exam Format, Delivery & Fee Structure
The COHN exam is a computer-based test developed and administered with Assessment Systems Corporation (ASC), ABOHN's contracted testing agency. Candidates may test at ASC test centers worldwide (in-person appointments are by appointment only, Monday through Saturday) or through Live Remote Proctoring (LRP), which ASC delivers through its partner MonitorEDU using a webcam plus a second mobile-camera device and live human proctors.
- Item Count & Composition: 160 multiple-choice items, of which 135 are scored and 25 are unscored pretest items. Pretest items cannot be distinguished from scored items and are used to vet questions statistically for future forms. Treat every question as scored.
- Time Allocation: 3 hours (180 minutes), an average of 1.125 minutes (67.5 seconds) per item. No breaks are provided during the examination; a candidate needing a break for a medical reason must submit an accommodation request with the application.
- New Forms: ABOHN develops new examinations annually and releases them every September/October, aligned to the reference list published at the time of development.
The fee structure has two mandatory components and one optional one. All ABOHN fees are non-refundable.
| Fee | Amount | What It Buys |
|---|---|---|
| Application | $150 | Eligibility review; approval is good for 90 days |
| Examination | $400 | Must be paid within 90 days of the invoice date; buys a 120-day testing authorization |
| Examination Authorization (Extension) | $50 | One-time 60-day extension added to the original 120-day authorization |
| Exam re-scoring (hand score) | $25 | Written request to ABOHN within 12 months of the exam |
| Yearly renewal / 5th-year recertification | $150 | Keeps the credential in Active status |
| Late fee | $100 | Charged for each year a renewal or recertification is late |
Exam Trap Warning: Two different 90-day clocks and one 120-day clock are easy to confuse. 90 days = how long you have to pay the exam invoice (and how long application approval lasts). 120 days = the window, starting when ABOHN transfers your file to ASC, in which you must schedule and sit the exam. The $50 extension adds 60 days to that 120-day window — not another 90. ABOHN and ASC allow only ONE change: either a one-time reschedule or an extension, never both.
Candidates forfeit all fees if they fail to contact ASC at least 2 business days before a scheduled appointment to reschedule, arrive more than 15 minutes late, fail to report, or fail to schedule within the 120-day period.
Standard-Setting & Score Reporting
ABOHN sets the minimum passing score using the Angoff method, applied during a Passing Point Study conducted by a panel of content experts:
- The expert panel evaluates each question on the examination to determine how many correct answers are necessary to demonstrate the knowledge and skills required for the credential.
- The standard is criterion-referenced: your result depends on your own ability to meet the standard, not on how other candidates performed. There is no curve and no fixed pass percentage.
- What the score report actually contains: a "pass" or "fail" decision, plus additional detail in the form of raw scores by major content category. A raw score is simply the number of questions answered correctly. Scores are reported in written form only.
Results are not given at the test center. ABOHN emails the pass/fail notification within 2 weeks of the examination, followed by an official pass/fail packet mailed during the 2nd or 3rd week of the month following the examination date.
Exam Trap Warning: ABOHN does not publish a scaled score or a fixed percentage cut score for the COHN, and it does not report one to you. If a prep resource tells you "you need a scaled 75," that claim has no basis in the current ABOHN handbook. What ABOHN publishes is the Angoff-derived passing point and raw scores by content category.
Candidates who do not pass may reapply — ABOHN imposes no limit on the number of attempts — but must wait 30 days from receiving their official results before reapplying, and must pay the application and examination fees again.
Maintaining the Credential: Annual Renewal + 5-Year Recertification
COHN certification is maintained through two separate obligations. Missing either one drops the credential out of Active status, and the credential may not be used once it has expired.
- Annual Renewal — an annual renewal application and fee ($150 for COHN/COHN-S), submitted every year of the cycle along with any updated work/home information.
- Recertification every 5 years — an application and fee, plus documentation of:
- Current, unrestricted RN licensure (or international equivalent).
- 50 continuing nursing education (CNE) contact hours related to occupational health, earned within the previous 5 years. (CM credential holders must submit an additional 10 case-management hours that cannot duplicate any of the 50.)
- 3,000 hours of occupational health nursing experience for paid compensation during the previous 5 years. You do not have to be currently employed when you apply for recertification.
Coursework toward a baccalaureate or graduate degree related to occupational health may substitute for some employment hours — but the same coursework may be used for either the continuing-education requirement or the work-experience requirement, never for both. A $100 late fee applies for each year a renewal or recertification is submitted after the expiration date; ABOHN sends reminders, but the credential holder is ultimately responsible for knowing when the paperwork is due.
A registered nurse who earned an Associate Degree in Nursing (ADN) 6 years ago has worked full-time in an occupational health clinic for the past 2 years, accumulating 3,800 hours of occupational health practice. Does this nurse meet the eligibility criteria for the ABOHN COHN exam?
During the 160-question COHN computer-based examination, how many items directly contribute to the candidate's final scored result, and how is the passing threshold established?
A nurse paid the COHN examination fee and was transferred to ASC on March 1. By late June the nurse still has not been able to sit the exam because of a family emergency, and has not yet rescheduled or cancelled anything. What option does ABOHN provide?