ABOHN COHN Exam 2026: The Complete Certified Occupational Health Nurse Playbook
The Certified Occupational Health Nurse (COHN) credential, issued by the American Board for Occupational Health Nurses (ABOHN), is the gold-standard certification for registered nurses who care for the working population. If you triage workplace injuries, run a respiratory-protection program, write return-to-work plans, audit ergonomics on a manufacturing floor, manage a hearing-conservation program, or coach employees through workers' compensation — COHN is the credential employers ask for by name.
This 2026 guide walks you through the exam end-to-end: the 160-question format, the five ABOHN content domains, eligibility hours, the critical COHN vs COHN-S decision, fees, the 5-year renewal cycle, and a 12-week study plan. Every linked resource is 100% free.
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COHN Exam Format at a Glance (2026)
| Spec | Detail |
|---|---|
| Total questions | 160 (135 scored + 25 unscored pretest) |
| Time limit | 3 hours (180 minutes) |
| Question type | Multiple-choice, four options, one best answer |
| Pass standard | Criterion-referenced (scaled passing score, not a fixed %) |
| Application fee | $400 USD per attempt (ABOHN, 2026) |
| Delivery | Computer-based at PSI Test Centers or live remote-proctored online |
| Renewal cycle | Every 5 years via Continuing Education or retest |
| Issuing body | American Board for Occupational Health Nurses (ABOHN) |
| Prerequisite | Active, unrestricted RN license + eligibility hours |
| Eligibility window after approval | 120 days to sit; one 60-day extension available for $50 |
| Approximate scaled pass mark | ~71% of scored questions correct |
| Score reporting | 8-12 weeks after testing, by mail (no electronic reporting) |
At roughly 80 seconds per scored question, time pressure is moderate — the failure mode is not speed but breadth. The COHN exam ranges across five distinct content domains, and most candidates underestimate just how much regulatory and case-management content sits inside what looks like a clinical exam.
COHN vs COHN-S: Which One Should You Take?
ABOHN offers two parallel certifications at the same price, sat from the same testing platform, but with very different content emphases. Picking the wrong one is the most common, expensive COHN mistake.
| Feature | COHN (Clinician) | COHN-S (Specialist) |
|---|---|---|
| Full title | Certified Occupational Health Nurse | Certified Occupational Health Nurse-Specialist |
| Education floor | Diploma, Associate's, or Bachelor's RN | Bachelor's degree (in any field) + active RN |
| Practice focus | Direct clinical care, triage, injury treatment, drug screens, surveillance | Program management, case management, OH leadership, education, consultation |
| Roles tested | Clinician, Coordinator, Advisor, Case Manager | Manager, Educator, Consultant, Case Manager, Clinician |
| Best fit | Floor-level OH RN, plant nurse, occupational triage clinic | OH program manager, corporate medical director RN, EHS lead, OH educator |
| Hours required (5-year practice route) | 3,000 hours OHN practice in last 5 years | 3,000 hours OHN practice in last 5 years |
| Fee | $400 | $400 |
Critical insight from ABOHN itself: "Just having a higher degree does not necessarily mean you should take the examination with the higher degree qualification." If your day-to-day is clinical (rooming employees, drawing labs, dispensing OTC, doing audiograms, fitting respirators), take COHN — even with a BSN. If your day-to-day is administrative (writing OSHA-compliance plans, leading FMLA case reviews, training supervisors, managing the OH budget), take COHN-S.
Review both Blue Prints (test specifications) in the ABOHN Handbooks before you apply. About 15% of COHN test-takers say in retrospect they should have taken COHN-S, and vice versa.
Eligibility: The Three Routes to Sit COHN
ABOHN offers three eligibility pathways. You only need to satisfy ONE.
Route 1 — Practice Hours (most common)
- Active, unencumbered RN license in your jurisdiction
- 3,000 hours of paid OHN practice completed in the past 5 years
- Hours can be from one employer or aggregated across multiple
- Hours must be in a role with the OHN scope of practice (clinical care, case management, surveillance, prevention) — not bedside hospital med-surg unless the patients are workforce-related
Route 2 — Academic Program Completion
- Active RN license
- Successful completion of an academic occupational health nursing program (graduate certificate, master's concentration, or equivalent recognized OH program)
- No minimum-hour count required if you finished a recognized academic program
Route 3 — Faculty
- RN license + you teach occupational health nursing in a recognized academic program
ABOHN audits ~10% of applications. Track every COHN-relevant hour in a spreadsheet from the day you accept your OH role: date, employer, role, supervisor, hours, and a one-line description of duties. Audited candidates without contemporaneous records routinely lose months waiting to reconstruct logs.
Documentation You Will Submit
- Application form ($400 fee)
- Copy of current RN license
- Detailed work history covering the 5-year window
- Verification letter from current OH supervisor or HR (template provided by ABOHN)
- For Route 2: official academic transcript and program description
Approval typically takes 4-6 weeks. Once approved, you have 120 days to schedule and sit the exam (a one-time 60-day extension is available for $50) — miss the window and you start over with a fresh $400 application.
Try a FREE COHN Practice Question Set
Our FREE ABOHN-style question bank covers all five domains with detailed AAOHN-grounded explanations.
The Five COHN Content Domains (Where Your 135 Scored Questions Come From)
ABOHN groups COHN content into five major practice areas. The exact percentage weights are published in the COHN Handbook each cycle; the 2026 weights below reflect the current Practice Analysis (review the latest Handbook before testing).
Domain 1 — Clinical Practice and Case Management (~40-45%)
The single largest domain. Expect roughly 55-60 of your 135 scored questions here.
Key topics:
- Triage and acute injury management — laceration care, sprains/strains, eye injuries, suspected fractures, burns, blood-borne pathogen exposures
- Workplace violence response and de-escalation
- Bloodborne-pathogen exposure protocol — source-patient testing, post-exposure prophylaxis (HIV PEP within 2 hours optimal, hepatitis B prophylaxis based on vaccination status)
- Return-to-work assessment — functional capacity evaluation, transitional duty, ADA reasonable accommodations
- Workers' compensation case management — communicating with adjusters, treating physicians, employer, and injured worker without violating dual-loyalty boundaries
- Chronic-disease management at the worksite (diabetes, hypertension, behavioral health)
- Travel health — pre-deployment screening, vaccinations, malaria prophylaxis
- Substance abuse evaluation — DOT vs non-DOT, chain of custody, medical review officer interaction
- Mental-health first response and EAP referral
Domain 2 — Worker Health Surveillance and Workplace Hazards (~20-25%)
Roughly 30-35 questions.
Key topics:
- Hazard recognition — chemical, physical, biological, ergonomic, psychosocial
- Occupational health surveillance programs — hearing conservation (annual audiogram + thresholds for STS), respiratory protection (OSHA 29 CFR 1910.134 medical clearance, fit testing), bloodborne pathogens, lead, asbestos, benzene, silica
- Toxicology basics — routes of exposure, dose-response, biological monitoring (blood lead, urine cadmium, urinary phenol)
- Industrial hygiene principles — hierarchy of controls (elimination → substitution → engineering → administrative → PPE), permissible exposure limits (PELs), threshold limit values (TLVs)
- Ergonomics — musculoskeletal disorder risk factors, NIOSH lifting equation, REBA/RULA assessments
- Indoor environmental quality — sick-building syndrome, mold, CO
- Heat illness prevention and management
Domain 3 — Regulatory, Legal, and Ethical Issues (~15-20%)
Roughly 22-28 questions. The most-failed domain by clinical-floor candidates.
Key topics:
- OSHA recordkeeping — 300 log, 301 incident report, 300A summary, recordable vs reportable, privacy concern cases
- OSHA general duty clause and key standards (HazCom, BBP, Respiratory, Hearing, Lockout/Tagout, PPE)
- HIPAA — when OH records ARE and ARE NOT covered (most OH records are employment records, NOT HIPAA-covered)
- ADA / ADAAA — direct threat, reasonable accommodation, post-offer medical exams
- Family and Medical Leave Act (FMLA) — eligibility, certification (form WH-380-E), intermittent leave
- Workers' Compensation — state-level variation, exclusive remedy doctrine
- Drug Testing — DOT regulations (49 CFR Part 40), random testing requirements, MRO process
- NIOSH, EPA, MSHA, FAA scopes — which agency does what
- AAOHN Code of Ethics — confidentiality, dual loyalty, employee advocacy
- Mandatory reporting — communicable disease, abuse, certain injuries
Domain 4 — Health Promotion and Maintenance (~10-15%)
Roughly 15-20 questions.
Key topics:
- Worksite wellness programs — design, ROI, EEOC voluntary-participation rules
- Tobacco cessation — 5 A's (Ask, Advise, Assess, Assist, Arrange)
- Cardiovascular risk reduction
- Cancer screening appropriate to working populations
- Behavioral health promotion — depression, anxiety, sleep, burnout
- Influenza and adult vaccination programs
- Health risk appraisals (HRAs) — interpretation and limits
Domain 5 — Research and Trends (~5-10%)
Roughly 8-12 questions.
Key topics:
- Evidence-based practice in occupational health
- Quality improvement methods (PDSA cycles, root-cause analysis)
- Basic statistics — incidence vs prevalence, sensitivity vs specificity, OSHA incidence rate calculation (cases × 200,000 / hours worked)
- Trends — workplace mental health, opioid epidemic in the workforce, total worker health (NIOSH framework), aging workforce, telework
What's New on the COHN Exam in 2026
The ABOHN Practice Analysis is refreshed roughly every five years to track the evolving OH nurse role. The 2026 exam reflects four meaningful shifts you should expect to see:
Shift 1 — Workplace Mental Health
Questions on suicide-risk screening, EAP utilization, psychological-safety culture, post-incident emotional first aid, and NIOSH Total Worker Health (TWH) framework integration are markedly more prominent than they were five years ago. Know the TWH model's premise: workplace conditions and personal-health risks are integrated, and OH nurses lead at that intersection.
Shift 2 — Return-to-Work and Stay-at-Work Programs
Expect 5-8 questions specifically on transitional duty, modified-duty plans, light-duty assignment, and the legal interplay between FMLA, ADA, and workers' compensation. Stay-at-Work programs (intervening before lost time occurs) are a 2026 emphasis.
Shift 3 — Infection Prevention Post-Pandemic
The pandemic-era playbook is now examined as standing OH practice: pandemic response planning, respiratory-protection-program ramp-up, contact tracing principles, and isolation/quarantine guidance for essential workers.
Shift 4 — Data and Outcomes
More questions on OH program metrics — incidence rate, severity rate, lost-time injury frequency rate (LTIFR), DART rate — and how to use them to demonstrate program ROI to the C-suite. Memorize the OSHA recordable incidence rate formula.
Build Your COHN Study Plan
Our AI builds a custom COHN study plan from your eligibility window, weakest domains, and target test date — 100% FREE.
Your 12-Week FREE COHN Study Plan
| Week | Focus | Hours | Tasks |
|---|---|---|---|
| 1 | Read AAOHN Standards of Practice + COHN Handbook Blue Print | 5 | Map your weakest domain |
| 2 | Domain 1 — Clinical Practice (acute injuries) | 6 | Triage protocols, eye/laceration/burn algorithms |
| 3 | Domain 1 — Case Management | 6 | RTW assessment, FCE, transitional duty letters |
| 4 | Domain 1 — Workers' Comp + BBP exposure | 6 | PEP timing, source testing, hep B prophylaxis decisions |
| 5 | Domain 2 — Hazard recognition + IH basics | 6 | Hierarchy of controls, PEL vs TLV, biological monitoring |
| 6 | Domain 2 — Surveillance programs | 6 | Hearing conservation thresholds, respirator medical clearance criteria |
| 7 | Domain 3 — OSHA recordkeeping deep dive | 8 | Recordable vs first-aid, 300/301/300A workflow, classic edge cases |
| 8 | Domain 3 — HIPAA, ADA, FMLA, Drug Testing | 8 | When HIPAA does/doesn't apply; direct-threat doctrine; intermittent FMLA |
| 9 | Domain 4 — Health promotion + Domain 5 — Research/Trends | 5 | Wellness ROI, NIOSH TWH, OSHA incidence rate math |
| 10 | First full-length 160-question timed mock | 6 | Score by domain |
| 11 | Weak-domain re-drill + flashcards | 6 | Target every missed concept |
| 12 | Second full-length timed mock + final review | 6 | Pace check, sleep, sit |
Total prep: 70-80 hours over 12 weeks. Fast-track candidates (active OH RN with 5+ years of practice) often pass with 40 hours; career-switchers from bedside nursing routinely need 100+ hours, especially on the regulatory domain.
Free and Low-Cost Resources
- AAOHN Standards of Occupational and Environmental Health Nursing (3rd edition) — the conceptual backbone the COHN exam tests against; AAOHN members access free, non-members can purchase
- OSHA.gov standards pages — free, authoritative; print 1910.134 (Respiratory), 1910.95 (Hearing), 1910.1030 (BBP), 1910.1200 (HazCom)
- NIOSH Total Worker Health framework at cdc.gov/niosh/twh — free overview articles
- AAOHN Continuing Education modules — many free for members
- OpenExamPrep COHN Practice Bank — Start FREE COHN Practice — unlimited AI-generated questions and explanations
AAOHN COHN/COHN-S Certification Review Course (the most popular paid prep)
If you want a comprehensive paid course, AAOHN's official Online Certification Review is the gold-standard prep. It's self-paced, covers 18 modules mapped to the ABOHN blueprint, and provides up to 16 contact hours of Continuing Nursing Education (CNE) that count toward future COHN renewal. 2026 pricing:
- AAOHN members: $419
- Non-members: $519
The 18 modules: Health Promotion · Case Management Role · Consultant/Advisor Role · Clinician Role · Principles of Leadership & Management · Psychological & Physiological Stress Management · Safety & Industrial Hygiene · Clinical Practice · Chronic Disease Management · Emergency Response · Physical Hazards & Ergonomics · Biohazards · Chemical Hazards (Pt. 1 & Pt. 2) · Information Management · Research · Standards & Regulations · Laws.
Most candidates who pass on the first attempt complete this AAOHN course alongside unlimited free practice questions (like ours), not instead of them. The course gives you the conceptual framework; practice questions calibrate your speed and pattern-recognition.
COHN vs Other OH Nurse Credentials
| Credential | Issuer | Cost | Format | Renewal | Best For |
|---|---|---|---|---|---|
| COHN | ABOHN | $400 | 160 Qs / 3 hr | 5 yr CE | Clinical OH RNs |
| COHN-S | ABOHN | $400 | 160 Qs / 3 hr | 5 yr CE | Manager/program-lead OH RNs with bachelor's |
| CCM (Certified Case Manager) | CCMC | $370 | 180 Qs / 3 hr | 5 yr CE | Case-management focus across populations |
| CHN-RN / CHN-S | ABOHN (case-management add-on) | Add-on certificate | Portfolio review | With base cert | Holders of COHN/COHN-S who want case-management designation |
| AAOHN membership | AAOHN | ~$285/yr dues | N/A | Annual | Continuing-education access, NOT a credential |
AAOHN is the professional association; ABOHN is the certifying body. They are separate organizations with distinct missions. Joining AAOHN gives you CE access and discounts but does not certify you. Passing the ABOHN COHN exam certifies you but is not membership in AAOHN.
OHN Salary in 2026
Occupational health nurses are well-compensated relative to general staff RNs because the role combines clinical, administrative, and regulatory expertise. 2026 BLS, Payscale, and Glassdoor data converge on these ranges:
| Role | US Median Salary 2026 |
|---|---|
| Entry-level OHN (0-2 yrs, no cert) | $70,000-$85,000 |
| COHN-certified clinical OH RN | $85,000-$105,000 |
| COHN-S program manager (5+ yrs) | $100,000-$125,000 |
| Senior OH program director | $115,000-$150,000 |
| Corporate OH consultant | $120,000-$160,000+ |
High-hazard sectors (oil & gas, construction, aerospace, mining) routinely pay 15-20% above these medians. Federal OH RN positions (VA, DOD, DOE national labs) carry locality-pay differentials and excellent benefits.
Certification ROI: ABOHN-certified OH RNs earn approximately $8,000-$12,000 more per year than uncertified peers in the same role, per multiple AAOHN compensation surveys. The $400 exam fee is recouped within the first month of the post-certification raise.
Test-Day Strategy
The Day Before
- Reread the OSHA recordkeeping decision tree (recordable vs first-aid). At least 4-6 questions WILL test edge cases
- Reread your HIPAA-vs-employment-records notes — "is this OH record HIPAA-covered?" is a near-guaranteed question
- Reread the bloodborne-pathogen post-exposure timing (PEP within 2 hours optimal, source testing protocols)
- Sleep 8 hours. Eat a real breakfast. Bring two forms of ID and your ABOHN authorization to test letter
During the 3 Hours
- First pass (90 minutes): answer everything you know cold. Flag the rest. Aim for ~90 questions answered confidently
- Second pass (60 minutes): return to flagged. Eliminate two wrong answers, then pick the one most aligned with AAOHN Standards language, not workplace-pragmatic logic
- Final pass (30 minutes): review every flagged question. Change an answer only if you find a clear AAOHN/OSHA citation in your head — not on a hunch
Golden rule: When two answers seem clinically equivalent, pick the one that protects the employee's confidentiality and AAOHN ethical principles first. The COHN exam consistently rewards employee-advocacy framing over employer-convenience framing.
Common Word Traps
- "Reportable" ≠ "recordable" on OSHA logs (reportable triggers a phone-in to OSHA: in-patient hospitalization, amputation, eye loss, fatality)
- "Direct threat" under ADA requires individualized assessment based on objective medical evidence — not assumption
- "Confidential" OH records are still subject to subpoena in workers' comp disputes
- "Light duty" and "transitional duty" are not interchangeable in every jurisdiction
Retake Policy and Renewal
Retake: If you fail, you may retake after 90 days with a fresh $400 application. Most candidates who retake pass on the second attempt because failed candidates receive a domain-by-domain score report that reveals exactly where to study. Score reports arrive 8-12 weeks after testing by mail — ABOHN does not currently offer electronic score delivery.
Renewal (every 5 years): Two paths to maintain your COHN:
- Continuing Education (CE) route — submit 50 contact hours of OH-relevant CE, plus practice-hour documentation, plus a $250 renewal fee
- Re-examination route — re-sit the COHN exam (same fee as initial)
Most certified OHNs choose the CE route. AAOHN, ABOHN-approved providers, and many state OH nurse associations offer the bulk of qualifying CE for free or modest cost.
Recertification Math: Plan for It from Year 1
The single biggest renewal mistake is letting CE accumulation slide until year 4. Build a 5-year CE log from the day you pass. Target 10 contact hours per year (50 total / 5 years), front-loading easy ones (free AAOHN webinars, OSHA training, NIOSH conferences) in the early years.
Qualifying CE categories (per ABOHN):
- AAOHN-approved continuing nursing education (CNE) — most flexible
- Academic coursework in OH or related fields (3 credit hours = 45 contact hours)
- Authoring published OH articles or chapters (capped contribution)
- Presenting at AAOHN, ANA, or other recognized OH conferences
- Volunteer teaching in accredited OHN programs
- Independent study with documented learning outcomes
Keep a CE folder (paper or cloud) with certificates of completion, contact-hour confirmations, and faculty/presentation evidence. ABOHN audits a percentage of renewal applications and reconstructing the trail is painful.
Renewal Fee Math (5-Year Cycle)
| Item | Cost |
|---|---|
| Renewal application fee | $250 |
| Average CE costs (50 hrs at ~$5/hr if paid; many free options exist) | $0-$250 |
| AAOHN annual dues (optional but reduces CE costs) | $285/yr × 5 = $1,425 |
| Total 5-year renewal cost (lean route) | $250-$500 |
| Total 5-year renewal cost (AAOHN-member route) | $1,675-$1,925 |
Most OH nurses join AAOHN regardless because it pays for itself in free CE within 18 months.
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COHN to COHN-S Career Ladder
Many OH nurses earn COHN early in their OH career, then add COHN-S after 5-7 years as their role moves into program management. ABOHN allows you to hold both credentials simultaneously by sitting both exams (each on its own renewal cycle). Holding COHN + COHN-S signals expertise across both clinical and administrative scopes — common in corporate OH directors and federal OH program leads.
The optional CHN (Case Management Nurse) add-on certificate from ABOHN is available to current COHN or COHN-S holders who want to formally recognize concentrated case-management practice. It's portfolio-reviewed (not a separate exam) and renews on the same cycle as your base credential.
Common COHN Mistakes (And How to Avoid Them)
Mistake 1: Treating It Like a Generic RN Exam
The COHN is not the NCLEX. Pathophysiology is light. Regulatory knowledge is heavy. If you ace clinical questions but flunk Domain 3 (regulatory/legal), you will fail. Allocate at least 25% of your study time to OSHA, HIPAA-employment-records distinctions, ADA, and FMLA.
Mistake 2: Confusing OSHA Recordable Criteria
Death, days away, restricted/transferred, medical treatment beyond first aid, loss of consciousness — these trigger recordability. First aid alone does not. Memorize the exact OSHA first-aid list (29 CFR 1904.7). The exam will give you four scenarios and ask which is recordable.
Mistake 3: Misapplying HIPAA to OH Records
Most OH records are employment records under HIPAA, NOT covered protected health information — provided the OH program is run by the employer. Records sent to a third-party billed health-plan benefit are different. Practice the decision tree.
Mistake 4: Wrong Bloodborne Pathogen Timing
HIV PEP is most effective started within 2 hours, but is generally still offered up to 72 hours. Hep B prophylaxis depends on source HBsAg status and exposed-worker vaccination history. Memorize the four-quadrant PEP decision matrix.
Mistake 5: Picking the Pragmatic Answer
When the exam asks what an OH nurse "should do," the right answer reflects AAOHN Standards and Code of Ethics, not what is fastest or cheapest. Employee advocacy and confidentiality nearly always beat employer convenience.
Mistake 6: Choosing COHN When You Should Sit COHN-S
Review the Blue Prints in both Handbooks. If your daily duties are 50%+ administrative (program management, policy writing, supervisor training, budget), COHN-S maps better.
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Official Resources
- ABOHN Certification Page — official exam information
- COHN/COHN-S Eligibility — current eligibility rules
- ABOHN Handbooks — Blue Prints with current domain weights
- AAOHN Standards of Practice — the conceptual framework the exam tests
- OSHA Standards 29 CFR 1910 — full text of the standards COHN tests
- NIOSH Total Worker Health — 2026 emphasis area
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