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Exams/Assisting/DANB-RHS

DANB-RHS · DANB (United States)

DANB-RHS
Safety.

Free 20-question DANB-RHS diagnostic, built from real exam-style items. See exactly where you stand across all 3 domains in about 30 minutes — no signup to start, instant topic-gap report.

20 questions · ~30 min · no signup to start · instant topic-gap report

Mock variants

4 ways to sit DANB-RHS.

Diagnostic

Free

20 items · 30 min

Free taster · topic gap analysis.

Topic Practice

Member

25 items · 35 min

25 items in a single domain.

Half Mock

Member

37 items · 30 min

Half of a real RHS sitting.

Full Mock

Member

75 items · 60 min

Full RHS sitting: 75 items in 60 minutes.

Blueprint · topic weights

3 domains, honestly weighted.

Diagnostic and mock items are sampled in proportion to the published DANB (United States) competency document — never random.

01Purpose and TechniqueImaging selection, exposure parameters, image quality, error recognition. Digital-only scope per DANB (film concepts out of scope since 2022-07-07).
50%
02Radiation Characteristics and ProtectionRadiation physics (kVp, mA, primary vs scatter), biological effects (deterministic vs stochastic, tissue radiosensitivity, Gy/Sv/R/rem dose units), ALARA, dose limits, shielding, monitoring, patient and operator protection (ADA + FDA radiation-protection guidelines are the DANB-named authorities).
25%
03Infection Prevention and ControlBarriers, sensor disinfection, digital workflow asepsis (CDC + OSHA aligned).
25%

FAQ

Everything candidates ask about DANB-RHS.

Who needs the DANB RHS?
The Radiation Health and Safety (RHS) exam is one component of DANB's Certified Dental Assistant (CDA) credential, required in U.S. states that mandate radiography certification before exposing patients. Many states accept RHS as the radiography licensure exam.
What is the DANB RHS format?
The RHS is a 75-item multiple-choice computer-based exam delivered in a 60-minute sitting, on digital radiography only. The blueprint splits roughly 50% Purpose and Technique, 25% Radiation Characteristics and Protection, and 25% Infection Prevention and Control.
What is the DANB RHS pass mark?
DANB uses a scaled score with 400 as the minimum passing score. Unofficial pass/fail is shown at the Pearson VUE testing centre at the end of the exam; the official score report follows by email within a few weeks.
How long should I study for the DANB RHS?
Most candidates allocate four to six weeks of focused prep — heavier on physics, exposure technique, and intraoral image error recognition. State-specific jurisprudence requirements are separate from DANB content.
How often can I retake the DANB RHS?
Per the 2026 DANB Candidate Handbook, there is no DANB-imposed limit on how many times a candidate may retake the RHS. Each attempt requires a new application + full fee (USD $270 traditional / $265 military). State boards may layer extra rules on top.
Does Lumen's RHS module count for state licensure?
Lumen is a study tool. The actual licensure exam is administered by DANB at Pearson VUE testing centres. We help you prepare; the credential is issued by DANB and recognized by your state board.
How do I sign up for Lumen?
You can take the free diagnostic without an account. To save attempts, see rationales, and unlock full mocks, sign in with email — we send a magic link, no password to forget.
Are rationales reviewed by clinicians?
Yes. Every item ships with a clinician-written rationale that cites the published competency guideline it maps to. Items flagged by users get re-reviewed within a business day.

Why Lumen for DANB-RHS

Built by clinicians, priced for students.

01

Blueprint-aligned items.

Topic weights match the published competency document. No guessing what the test cares about.

02

Every rationale signed.

A licensed clinician wrote, reviewed, and cited every explanation. Flag one and we re-review within a day.

03

Diagnostic before you pay.

Free 20-item diagnostic with full topic gap analysis. No credit card. Decide if we’re right for you, then upgrade.

Independent study tool. Not endorsed by NDEB, ADA, or JCNDE. We do not promise passing scores. All items are exam-style and based on publicly available competency guidelines.