About the DANB RHS Exam

About the DANB RHS Exam

Quick Answer: The Dental Assisting National Board (DANB) Radiation Health and Safety (RHS) exam is 75 multiple-choice questions in 60 minutes. You need a minimum scaled score of 400 on a 100–900 scale. The traditional fee is $270 ($265 active military). There are no eligibility requirements. RHS is a component of both NELDA and CDA, and the outline effective 03/12/2025 weights Purpose and Technique at 50%, Radiation Characteristics and Protection at 25%, and Infection Prevention and Control at 25%.

The Radiation Health and Safety (RHS) exam is DANB’s national knowledge exam for dental radiography safety and technique. DANB’s purpose statement is practical: RHS verifies that candidates meet a minimum national standard for radiation health and safety tasks that protect patients and oral healthcare workers. Passing RHS does not by itself grant a state license or authorize every radiographic duty—state dental boards still set who may expose images—but a passing RHS result is the credential many employers, schools, and state pathways recognize as proof of radiography competence.

Exam logistics you must memorize

Treat the logistics as non-negotiable facts, not background color:

Sixty minutes for 75 items averages about 48 seconds per question. That pace rewards candidates who already know landmarks, error patterns, ALARA rules, and infection-control workflows—not candidates who hope to “figure it out” under the clock. Build timed sets early; free practice at /practice/danb-rhs is designed for that cadence.

Results are scaled scores, not percent-correct. A 400 is the criterion-referenced pass line DANB sets with a modified Angoff process. You will not see a raw “you got 52 of 75” as your official result. Email notification typically arrives within 1–3 business days, with the score in your online DANB account. Eligible candidates who do not pass may qualify for a one-time retake discount under current DANB fee rules—confirm the active packet before you reapply, but do not plan your first attempt around a discount.

Who should take RHS—and why there is no eligibility gate

DANB states there are no eligibility requirements to take RHS. You do not need a completed dental assisting program, a certain number of chairside hours, or employer sponsorship to apply. That open-entry design is intentional: RHS is both a stand-alone competence check for radiography knowledge and a component exam inside larger DANB certifications.

Two certification stacks use RHS:

• NELDA (National Entry Level Dental Assistant): AMP (Anatomy, Morphology and Physiology) + RHS + ICE (Infection Control)
• CDA (Certified Dental Assistant): RHS + ICE + GC (General Chairside Assisting)

If your goal is NELDA or CDA, RHS is not optional—it is one of the three required component passes. If your goal is only to document radiography knowledge for a job or a state that recognizes DANB RHS, you can sit RHS alone. Either way, the exam content and pass standard are the same. Open eligibility also means high school students, career changers, and currently employed assistants all face the identical outline—so do not assume “I work chairside, so Domain I will be easy.” Clinical exposure helps, but the exam still tests named image purposes, angulation error names, dose units, and CDC/OSHA-framed radiography infection control.

Domain weights: study like the outline scores

The RHS Exam Outline effective 03/12/2025 assigns:

1. Purpose and Technique — 50%
   Image types and purposes (PA, bitewing, FMS, occlusal, panoramic, cephalometric, CBCT), diagnostically acceptable features, paralleling and bisecting, panoramic technique, modifications for tori/shallow palate/narrow arch, error correction (exposure, placement, angulation, motion, artifacts), receptor care (PSP, CCD, CMOS), mounting/viewing, and legal image maintenance (HIPAA, retention, ownership).

2. Radiation Characteristics and Protection — 25%
   Production factors (kVp, mA, time), primary vs scatter, biology (sensitivity, latent/recovery periods, genetic vs somatic), dose units (Gy, Sv, R, rem, C/kg), MPD and ALARA, operator position-distance-barrier rules, filtration/collimation/PID, patient concerns and informed consent/refusal, malfunction protocols.

3. Infection Prevention and Control — 25%
   Standard precautions for radiographic equipment and supplies (barriers, clinical contact surfaces, Spaulding categories for items used in imaging), plus hand hygiene, PPE, and cross-contamination control during exposures—aligned with ADA, CDC, and OSHA expectations.

Half the exam is technique. If your study calendar is “equal thirds,” you are under-preparing Domain I. A practical split for a 60-hour plan is roughly 30 hours technique, 15 hours radiation protection, 15 hours infection control—then mix timed mixed-domain sets so topic switching does not surprise you. When you review misses, tag each one to a domain and rebalance the next week’s hours toward whichever domain is leaking points.

How to use this guide chapter

This “About” chapter locks the exam’s identity: format, fee, pass score, open eligibility, NELDA/CDA role, and 50/25/25 weighting. Later chapters teach the outline topics themselves—image purposes, paralleling versus bisecting, ALARA controls, and radiography-specific infection control. Before you dive into those skills, confirm you can recite the logistics table cold and that your study hours match Domain I’s 50% weight. When you are ready to pressure-test recall under a 60-minute clock, use /practice/danb-rhs alongside the official outline—not instead of it.