No, the study resources for the CDI exam are available at no cost on the UniversiDI website.

The most effective approach is to create a study plan that balances reviewing core content with practicing application-based questions. Start by reviewing the CDI Exam Content Outline to understand the topics that will be covered, then take a practice test on the UniversiDI website to get a feel for the question style and identify strengths and areas for improvement. From there, use the study guide, review recommended references, attend a live or on-demand review session, and incorporate any training materials from your workplace. As you study, set aside consistent time each week and consider joining a study group for accountability and discussion. Once you feel prepared, take another practice test to measure your progress and build confidence.

Preparation time varies depending on your background and experience. On average, candidates spend between 1 and 6 months studying, devoting a few hours each week. If you’re newer to the field, you may want to give yourself more time to review key concepts. If you have several years of experience, you may need less time, but you should still plan for focused review sessions to refresh your knowledge and skills with the exam format.

Feeling nervous is completely normal. A structured and consistent study plan can help reduce anxiety by building familiarity with the content and exam format. The UniversiDI website includes tools to help you create and follow that plan, such as the digital CDI Planner, practice tests, flash cards, and the CDI study guide. These resources are designed and reviewed by subject matter experts to align directly with the CDI exam.

Practice questions are especially helpful for reducing uncertainty about what to expect. Be sure to take regular breaks during study sessions to avoid burnout, and use stress-management techniques such as deep breathing, stretching, or short walks. On exam day, aim for a good night’s sleep, eat a balanced meal, and arrive early to your exam session so you feel calm and prepared.

Yes. While professional experience provides a strong foundation, the exam is designed to assess knowledge and skills across the full scope of disease intervention practice. Studying ensures you refresh less familiar topics, understand how material is presented in a testing environment, and build confidence with the exam format. Even seasoned professionals benefit from a structured review to perform at their best on test day.

Unlike degrees and certificate programs, certifications must be maintained over time. Maintenance of the CDI credential ensures that certificants are staying current on emerging trends and best practices in the field of disease intervention and continuing to meet a national standard. Recertification also contributes to ongoing professional development through lifelong learning.

The recertification period for the CDI is 3 years. Review the CDI Recertification Requirements webpage.

CDI certificants must earn a total of 30 recertification credits during the 3-year recertification period.

There is a fee of $95 due when you submit your recertification application.

Public health and disease intervention related activities that relate to the CDI Content Outline such as work experience, conferences, publications, presentations, courses, webinars, workshops, and volunteer activities can count towards recertification. The CDI Recertification Activities Credit Guide has a full list of activities that count towards recertification.

Unlike other professional licenses or credentials, CDI certificants do not have to attend certain paid trainings or events to recertify. The recertification credits you earn can be from any organization/provider. NBPHE does not have a list of authorized providers for recertification activities. NBPHE accepts any public health or disease intervention related activity for recertification as long as it fits in the categories listed in the CDI Recertification Activities Credit Guide. In fact, many CDIs earn credits by participating in webinars, conferences, meetings, and events through their job.

Each hour (60 minutes) spent participating in a recertification activity equals one recertification credit.

If the amount time you spend participating in a recertification activity does not equal a whole number, you can round up to the nearest whole number. For example, a disease intervention related webinar that lasts 1.5 hours can count for 2 credits.

Yes, CDI Certificants can earn 10 recertification credits per 3-year cycle for work experience.

 Yes! Your volunteer service such as participating in a community outreach event, joining a public health awareness event, or being a member of a board or committee (e.g., item writer/ reviewer, study guide, passing score study, exam review, job task analysis)  will count towards CDI recertification.

If you are not sure whether an activity will count towards recertification, you can email a brief description of the activity to NBPHE staff at [email protected] to request guidance.