- The 2026 CDN Pass Rate Snapshot
- Why This Number Matters More Than You Think
- How Domain Weighting Drives the Pass Rate
- Who Tends to Pass - and Who Doesn't
- Scoring Mechanics: Why 70% Isn't Always 70%
- Eligibility Rules and Their Effect on Attempt Quality
- The March 2026 Blueprint Change
- A Domain-Weighted Prep Timeline
- The Real Cost of Not Passing the First Time
- Frequently Asked Questions
- The official 2025 CDN pass rate was 65% across 356 administrations - roughly one in three candidates did not pass.
- Chronic HD Unit (ESRD) alone makes up 52% of the exam, making it the single biggest factor in pass/fail outcomes.
- A passing standard score of 95 corresponds to about 70% correct on roughly 125 scored items.
- Retakes cost $200 ($175 for partner members), so first-attempt preparation has real financial weight.
The 2026 CDN Pass Rate Snapshot
The Nephrology Nursing Certification Commission (NNCC), which administers the Certified Dialysis Nurse (CDN) exam in partnership with the Center for Nursing Education and Testing (C-NET), reported an official 2025 pass rate of 65% across 356 administrations. That figure is the most concrete data point available for anyone trying to gauge how difficult the CDN exam really is, and it deserves more scrutiny than a passing glance.
A 65% pass rate means over a third of test-takers - experienced nephrology RNs who met strict eligibility requirements before ever sitting down at a PSI testing center - did not clear the standard score of 95. These are not unqualified candidates. They are working nurses with substantial hemodialysis experience. That context alone should reshape how you think about preparation. For a broader breakdown of exactly what makes this exam challenging, see our complete difficulty guide to the CDN exam.
Why This Number Matters More Than You Think
Pass rate data matters for two practical reasons. First, it tells you the CDN exam is not a rubber-stamp credential - nephrology employers and hiring managers know this, which is part of why the credential carries weight on a resume. Second, it should inform your own risk tolerance around retakes. At $350 for a standard first attempt (or $300 for members of ANNA, ASN, NKF, or NOVA), plus a $200 retake fee ($175 for partner members), failing isn't just discouraging - it's an added cost most nurses would rather avoid. For the full fee breakdown, including what's refundable and what isn't, check the CDN certification cost breakdown.
The takeaway isn't to be intimidated by the 65% figure. It's to treat CDN preparation as a structured project rather than a review skim the week before your test date. Our CDN study guide for passing on the first attempt goes deeper into building that structure.
How Domain Weighting Drives the Pass Rate
The CDN exam is built from four content domains, and their weighting is dramatically uneven. This imbalance is probably the single biggest driver behind why some well-prepared candidates still fall short of the standard score.
Domain 1: Chronic HD Unit (ESRD) - 52%
This domain alone accounts for more than half the scored items on the exam. It covers the day-to-day realities of managing chronic in-center hemodialysis patients - vascular access complications, dialysis prescription adjustments, fluid and electrolyte management, medication administration, and complication recognition during treatment.
- Vascular access types, complications, and troubleshooting
- Intradialytic complications and appropriate nursing response
- Fluid removal calculations and dry weight assessment
Domain 2: Concepts of Kidney Disease in Adults - 32%
This domain tests foundational nephrology pathophysiology - how chronic kidney disease progresses, comorbid conditions like diabetes and hypertension, lab value interpretation, and the broader disease process that leads patients into dialysis in the first place.
- CKD staging and progression markers
- Lab value interpretation (BUN, creatinine, potassium, phosphorus)
- Comorbidity management in the CKD population
Domain 3: Chronic HD Unit (AKI & DGF) - 8%
A smaller domain focused on acute kidney injury and delayed graft function - situations distinct from chronic ESRD management, often involving hospitalized or post-transplant patients.
- Distinguishing AKI etiologies from chronic ESRD presentations
- Delayed graft function recognition and dialysis-related management
Domain 4: Water for Dialysis - 8%
Covers water treatment systems, quality standards, and the technical side of dialysis water safety - a domain many bedside nurses underestimate because it's less clinical and more technical/mechanical.
- Water treatment system components and monitoring
- Water quality standards and contamination risks
Notice the math: Domains 1 and 2 combined make up 84% of the scored exam. Yet many candidates instinctively spend equal time across all four domains because that "feels" balanced. It isn't. For a full walkthrough of every domain with topic-by-topic detail, see our complete guide to all four CDN exam content areas.
Key Takeaway
Since Chronic HD Unit (ESRD) is 52% of the exam, under-preparing this single domain is statistically the most common way candidates land below the standard score of 95.
Who Tends to Pass - and Who Doesn't
NNCC doesn't publish demographic breakdowns of who passes and who doesn't, so any claim about "typical" pass/fail profiles beyond the aggregate 65% figure would be speculation. What we can say, based on the eligibility structure and exam design itself, is that the exam rewards candidates with two things:
- Recent, hands-on chronic in-center hemodialysis experience - not just general nephrology floor experience, since Domain 1 is so heavily weighted toward ESRD unit management.
- Deliberate exposure to Domain 4 topics - water treatment is a technical area rarely covered in daily bedside routines, so nurses who skip dedicated review of it often lose points here despite being otherwise strong clinicians.
If you're unsure whether your current role and hour count even qualify you to sit for the exam, review our detailed CDN eligibility and requirements guide before focusing on content review.
Scoring Mechanics: Why 70% Isn't Always 70%
The CDN exam uses an Angoff-derived criterion-referenced scoring standard, not a simple raw-percentage cutoff. The exam includes 150 four-option multiple-choice questions total, but only about 125 are scored - the remaining roughly 25 are unscored pilot items being tested for future exam versions. You won't know which items are which, so every question must be treated as if it counts.
The passing standard score of 95 is currently described as corresponding to 70% correct on the scored items. Because scoring is criterion-referenced rather than purely percentage-based, the practical cutoff can shift slightly between exam forms based on item difficulty - which is exactly why NNCC frames the passing mark as a standard score rather than a fixed raw percentage. For the full mechanics of how this scoring model works, read our dedicated breakdown of the CDN passing score and what it actually requires.
Eligibility Rules and Their Effect on Attempt Quality
Unlike entry-level nursing certifications, the CDN exam has meaningful eligibility gates before you ever register:
- A full, unrestricted U.S. or territorial RN license
- 2,500 hours of nephrology RN experience in chronic in-center hemodialysis care, or in educating/supervising such staff, within the prior 2 years
- 30 approved nephrology continuing-education contact hours completed within the prior 2 years
These requirements filter out candidates who lack direct exposure to the material - which is part of why the pass rate isn't higher despite a fairly experienced applicant pool. Meeting the minimum hour threshold doesn't guarantee deep familiarity with every domain, especially the smaller ones like AKI/DGF and water treatment, which a nurse working strictly chronic ESRD shifts may rarely touch. Review the specifics in our CDN requirements and eligibility breakdown if you're mapping your own qualifying hours.
The March 2026 Blueprint Change
A detail every 2026 test-taker needs on their radar: a revised exam blueprint takes effect for examinations administered on or after September 1, 2026. Examinations given through August 31, 2026 will still follow the prior content outline.
This matters for two groups of candidates:
- Anyone testing before September 1, 2026 should study against the current domain weighting described in this article, without worrying about blueprint changes.
- Anyone testing on or after September 1, 2026 should confirm they're studying the updated content outline once NNCC publishes the specifics, rather than relying on older prep material built around the prior blueprint.
Since testing is offered year-round at PSI sites, you have flexibility in choosing which side of that date to schedule on - plan accordingly. See our CDN exam dates and testing window guide for scheduling mechanics.
Key Takeaway
If your test date is close to September 1, 2026, confirm which blueprint version applies before finalizing your study materials - using the wrong outline wastes preparation time.
A Domain-Weighted Prep Timeline
Generic study techniques - spaced review, timed practice blocks, self-testing - only help if they're pointed at the right material in the right proportion. Given that Domain 1 (52%) and Domain 2 (32%) make up 84% of the scored exam, your study calendar should mirror that weighting rather than splitting time evenly across four domains.
Chronic HD Unit (ESRD) Deep Dive
- Vascular access management, intradialytic complications, fluid/electrolyte protocols
- Timed practice sets focused exclusively on Domain 1 scenarios
Concepts of Kidney Disease in Adults
- CKD staging, lab value interpretation, comorbidity management
- Cross-reference with Domain 1 material where ESRD and CKD concepts overlap
AKI/DGF and Water for Dialysis
- Concentrated review of the two smaller domains - don't skip them despite lower weighting
- Full-length timed practice exam under 3-hour conditions
Review and Weak-Area Correction
- Revisit missed questions from practice exams, grouped by domain
- Light review only - avoid cramming new material days before test day
For a condensed, printable version of the highest-yield facts across all four domains, our CDN cheat sheet with must-know facts is designed exactly for this final review week. And if you want to build full-length practice under real timing pressure, our CDN practice test platform is structured around this same domain weighting.
The Real Cost of Not Passing the First Time
Beyond the emotional toll, failing the CDN exam has a direct financial and scheduling cost: a $200 retake fee ($175 for partner members), plus whatever time you spend re-preparing before your next PSI testing slot. Compare the standard first-attempt and retake costs below.
| Attempt Type | Standard Fee | Partner Member Fee |
|---|---|---|
| First Attempt | $350 (includes $50 nonrefundable processing fee) | $300 |
| One-Time Retake | $200 | $175 |
Given that a 65% pass rate means roughly one in three candidates needs a retake, treating the exam fee as a "one-shot" investment - and preparing accordingly - is the more cost-effective mindset. If you're weighing whether the certification is worth this investment relative to career impact, our complete ROI analysis of CDN certification and CDN salary guide both dig into that question with real numbers.
It's also worth remembering that certification isn't a one-time event - it's valid for 3 years and requires either re-examination or renewal via 1,500 nephrology RN hours and 45 continuing-education contact hours (including at least 15 nephrology-specific hours) to maintain. Passing well the first time sets a stronger foundation for that renewal cycle down the road.
Frequently Asked Questions
NNCC reported a 65% pass rate across 356 administrations in 2025. This is the most recent official figure available for the CDN exam.
Meeting the 2,500-hour eligibility requirement confirms clinical exposure, but it doesn't guarantee balanced familiarity across all four domains - particularly the smaller Water for Dialysis and AKI/DGF domains, which are easy to underweight during self-study.
No penalty for incorrect answers is described in NNCC's exam structure, so leaving a question blank forfeits a chance at credit that a guess wouldn't. Answer every question within your 3-hour window.
It depends on your test date. Examinations through August 31, 2026 use the prior outline; examinations on or after September 1, 2026 use the revised blueprint. Confirm your scheduled date before choosing study materials.
Of the 150 total multiple-choice questions, about 125 are scored and roughly 25 are unscored pilot items. You won't be told which are which, so every question should be answered carefully.