DANB RHS Exam FAQ (2026)
Answers to the most common DANB Radiation Health & Safety (RHS) questions: passing score (400), exam format, the four blueprint domains, radiation safety, and how to prepare with Unlimited Practice Guide.
- What is the RHS exam?
- The Radiation Health and Safety (RHS®) exam is a DANB certification — both a standalone credential and one of the three component exams (with GC and ICE) that make up the CDA®. Many states require it before a dental assistant may take radiographs.
- What is the passing score for the RHS exam?
- DANB uses a 100–900 scaled scoring system; the RHS passing score is 400. Scaled scores adjust for form difficulty and are not raw percentages.
- How many questions are on the RHS exam?
- 100 questions in a 90-minute timed session, delivered at Pearson VUE testing centers.
- What content areas does the RHS exam cover?
- Four weighted domains: Radiation Physics & Equipment (35%), Radiographic Technique (30%), Radiation Safety & Protection (25%), and Infection Control (10%).
- What is the ALARA principle?
- "As Low As Reasonably Achievable" — the core radiation-safety principle behind questions on collimation, filtration, exposure settings, and protective barriers.
- How do I register for the RHS exam?
- Register at danb.org, create a My DANB account, verify eligibility, pay the exam fee, and schedule via Pearson VUE after approval.
- How long should I study for the RHS exam?
- Most candidates spend 2–3 weeks, prioritizing radiation physics and safety, which together account for 60% of the exam.
Ready to Start Practicing?
230+ RHS-aligned questions across all four domains, a full timed mock exam, and adaptive CAT simulation — included with DANB Pro on Unlimited Practice Guide.
Start RHS Practice