The Certified Dialysis Nurse (CDN®) credential is designed for registered nurses who care for patients receiving in-center hemodialysis. The certification exam, administered by the Nephrology Nursing Certification Commission (NNCC®), measures the knowledge and clinical judgment needed to provide safe, effective dialysis nursing care.
What Is the CDN Certification?
CDN stands for Certified Dialysis Nurse. The credential is offered by the Nephrology Nursing Certification Commission (NNCC) for registered nurses whose practice focuses on patients receiving in-center hemodialysis.
The CDN exam is intended to confirm that a nurse has the knowledge and skills needed to practice competently in a dialysis setting. This includes understanding kidney disease, hemodialysis treatments, dialysis equipment and water systems, medications, infection prevention, patient education, and complications that can occur before, during, and after treatment.
CDN vs. CNN: The CDN credential is specifically focused on nurses working with patients who require in-center hemodialysis. The Certified Nephrology Nurse (CNN®) credential covers a broader nephrology scope that can include acute care, home therapies, chronic kidney disease management, and transplantation.
Who Is Eligible for the CDN Exam?
To qualify for the CDN exam in the United States or its territories, you must meet all three of the following requirements:
- Hold a current, full, and unrestricted RN license in the United States or one of its territories.
- Complete at least 2,500 hours of qualifying nephrology nursing experience during the two years before applying. The experience must involve caring for patients who require in-center hemodialysis or educating or supervising staff who provide that care.
- Complete 30 contact hours of approved continuing education in nephrology nursing during the two years before applying.
The continuing education must come from an accepted provider, such as an organization accredited through the American Nurses Credentialing Center Commission on Accreditation, the American Association of Critical-Care Nurses, the Council of Continuing Education, or a state board of nursing.
Degree requirement: A BSN is not required for the current CDN certification pathway. NNCC’s 2026 changes moved the focus to the nurse’s professional role and qualifying dialysis experience rather than degree level.
How Is the CDN Exam Structured?
The current CDN exam contains 150 multiple-choice questions and must be completed within 3 hours.
Approximately 25 questions are experimental or pilot questions that are being evaluated for possible use on future exams. These questions are not scored, but they are mixed throughout the test and are not identified. You should therefore answer every question as though it counts.
| Exam Feature | Current Format |
|---|---|
| Total questions | 150 |
| Approximate scored questions | 125 |
| Approximate pilot questions | 25 |
| Time limit | 3 hours |
| Format | Computer-based |
What Is on the CDN Exam?
A new CDN exam blueprint took effect September 1, 2026. The current test is much more specifically focused on in-center hemodialysis than the previous version.
CDN Content Areas
| Content Area | Percentage |
|---|---|
| Chronic Hemodialysis Unit — ESRD | 52% |
| Concepts of Kidney Disease in Adults | 32% |
| Chronic Hemodialysis Unit — AKI & DGF | 8% |
| Water for Dialysis | 8% |
1. Chronic Hemodialysis Unit — ESRD
This is by far the largest portion of the exam, accounting for 52% of all questions. It focuses on nursing care in a chronic in-center hemodialysis environment for patients with end-stage kidney disease.
Areas you should understand include:
- Patient assessment before, during, and after hemodialysis
- Vascular access assessment and complications
- Dialysis prescriptions and treatment parameters
- Fluid management and target weight
- Common intradialytic complications
- Dialysis adequacy
- Medication administration and monitoring
- Infection prevention
- Emergency and disaster procedures
- Patient education and interdisciplinary care
2. Concepts of Kidney Disease in Adults
This section accounts for 32% of the exam and focuses on the underlying clinical concepts that affect adult patients with kidney disease.
Topics may involve:
- Kidney anatomy and physiology
- Chronic kidney disease
- Electrolyte and acid-base abnormalities
- Anemia
- Mineral and bone disorders
- Cardiovascular complications
- Nutrition and fluid balance
- Laboratory values
- Medication considerations
- Complications associated with kidney failure
3. Chronic Hemodialysis Unit — AKI & DGF
Approximately 8% of the exam deals with patients receiving hemodialysis in the chronic dialysis unit because of acute kidney injury (AKI) or delayed graft function (DGF) following kidney transplantation.
You should understand how the assessment, treatment, monitoring, and nursing needs of these patients can differ from those of patients receiving long-term dialysis for end-stage kidney disease.
4. Water for Dialysis
The final 8% of the exam focuses specifically on the water systems used to produce safe dialysis fluid.
Areas may include:
- Water-treatment components
- Reverse osmosis
- Carbon tanks
- Water softeners
- Distribution systems
- Monitoring and testing
- Microbiological contamination
- Chemical contaminants
- Responding to unsafe water conditions
What Skills Are Tested?
In addition to the four clinical content areas, every exam question is also associated with one of seven objectives.
| Objective | Percentage |
|---|---|
| Select appropriate interventions | 22% |
| Apply physiologic and technical principles | 20% |
| Recognize pathologic processes and complications | 18% |
| Medication administration | 14% |
| Patient, family, and professional teaching | 10% |
| Infection prevention and control | 8% |
| Collaboration and administration | 8% |
The largest objective is selecting appropriate nursing interventions, followed closely by applying the physiologic and technical principles of kidney replacement therapy. That means preparation should involve more than memorizing terminology. You need to be able to apply clinical information to realistic dialysis situations.
How Much Does the CDN Exam Cost?
The standard CDN examination fee is currently $350. Members of certain NNCC partner organizations qualify for a reduced examination fee of $300.
| Fee | Amount |
|---|---|
| Standard examination fee | $350 |
| Partner-member examination fee | $300 |
| Standard one-time retake | $200 |
| Partner-member one-time retake | $175 |
| 90-day testing-window extension | $125 |
Partner organizations currently include the American Nephrology Nurses Association, American Society of Nephrology, National Kidney Foundation, and Nurses Organization of Veterans Affairs.
How Do I Register for the CDN Exam?
You can submit a CDN examination application after meeting the licensure, experience, and continuing-education requirements.
The application requires documentation of your RN license, nephrology continuing education, qualifying employment, and other identifying information. Your supervisor must verify your qualifying in-center hemodialysis experience.
After NNCC approves your application, you will receive an examination permit with instructions for scheduling your computer-based exam.
Scheduling window: Your examination permit is generally valid for 90 days. Computer-based NNCC examinations are available year-round at PSI testing locations, so you choose an available appointment within your eligibility window.
What Should I Expect on Test Day?
The CDN exam is computer-based. Bring the required current government-issued photo identification and follow the instructions included with your examination permit and scheduling confirmation.
Personal study materials cannot be used during the exam. The questions do not require calculations that need a calculator.
You have three hours for 150 questions, which works out to an average of about 72 seconds per question. There is no penalty for guessing, so you should answer every question even if you are unsure.
How Is the CDN Exam Scored?
NNCC uses a predetermined passing standard rather than grading candidates against one another. Its current CDN information identifies a standard score of 95 as the passing benchmark.
Because approximately 25 questions are unscored pilot items, your final result is based on the scored portion of the exam. You cannot identify the pilot questions while testing.
Computer-based test takers receive their score report immediately after completing the exam. Candidates who do not pass also receive subscores for the major content areas, which can help identify what to study before another attempt.
What Happens If I Don’t Pass?
If you do not pass the CDN exam, NNCC provides one opportunity within one year to retake the examination at the reduced retest rate.
The current retest fee is $200 for standard applicants and $175 for eligible partner-organization members.
How to Prepare for the CDN Exam
The September 2026 blueprint makes study priorities much clearer. More than half of the examination focuses specifically on the chronic hemodialysis unit, so treating every area of nephrology as equally important is not an efficient study strategy.
- Put chronic in-center hemodialysis first. Chronic HD Unit — ESRD accounts for 52% of the exam and should receive the largest share of your study time.
- Build a strong kidney-disease foundation. Concepts of Kidney Disease in Adults accounts for another 32%, meaning those two domains together make up 84% of the test.
- Do not ignore the water system. Water for Dialysis is only 8% of the exam, but these are specialized concepts that can be difficult to answer from general nursing knowledge alone.
- Practice choosing nursing interventions. Selecting the appropriate intervention is the single largest objective category at 22%.
- Review technical dialysis principles. Understand how hemodialysis works rather than only memorizing equipment names or definitions.
- Practice under a time limit. Work toward maintaining a pace of roughly one question every 72 seconds while still reading each clinical scenario carefully.
CDN Study Resources
How Long Is CDN Certification Valid?
The CDN credential is valid for three years. You can maintain certification either by taking the certification exam again or by meeting NNCC’s continuing-education recertification requirements.
For recertification through continuing education, current requirements include:
- A current, full, and unrestricted RN license
- At least 1,500 hours of nephrology nursing experience during the three-year certification period
- 45 accredited nursing continuing-education contact hours during the certification period
- At least 15 of those 45 hours in nephrology
The standard recertification fee is currently $175 when recertifying through continuing education or $350 when recertifying by examination.
Bottom line: The current CDN exam is heavily focused on in-center hemodialysis. Prioritize chronic hemodialysis care and adult kidney-disease concepts, then make sure you are comfortable applying technical dialysis principles, selecting appropriate nursing interventions, managing medications, preventing infection, and understanding dialysis water systems.
