- The CER has 150 questions total-125 scored and 25 unscored-across 7 domains in 3 hours at a Prometric center.
- Domain 4 (Endoscope Processing Steps) accounts for 32% of scored questions, making it the single most important area to master.
- Practice questions should mirror the clinical, scenario-based style of the actual exam-not just vocabulary definitions.
- HSPA uses Angoff/Beuk criterion-referenced scoring; there is no publicly released numeric cut score to target.
What CER Exam Questions Actually Look Like
Most candidates who struggle with the Certified Endoscope Reprocessor exam do so not because they lack knowledge, but because they practice with the wrong type of questions. The CER, administered by the Healthcare Sterile Processing Association (HSPA) through Prometric Testing Centers, is not a recall quiz. Every item is a four-option multiple-choice question written to assess whether a reprocessing professional can apply knowledge in a realistic clinical scenario.
That means a question about manual cleaning will not simply ask you to define "detergent." It will present a situation-a colonoscope just returned from a procedure room, a technician making a decision about water temperature, or a quality-control failure in a high-level disinfection log-and ask what the correct action or interpretation is. Understanding this distinction is the foundation of effective practice.
For a broader understanding of difficulty and what separates passers from repeaters, see our article on How Hard Is the CER Exam? Complete Difficulty Guide 2026.
Domain-by-Domain Question Focus
The May 2022 CER content outline divides the exam into seven domains. Knowing the weight of each domain is the single most strategic piece of information for building a practice question bank. Here is how the scored questions are distributed:
| Domain | Weight | Approx. Scored Questions (of 125) |
|---|---|---|
| Domain 1: Microbiology and Infection Control | 12% | ~15 |
| Domain 2: Endoscope Purpose, Design and Structure | 10% | ~13 |
| Domain 3: Work Area Design | 12% | ~15 |
| Domain 4: Endoscope Processing Steps | 32% | ~40 |
| Domain 5: Endoscope Handling, Transport and Storage | 16% | ~20 |
| Domain 6: Endoscope Tracking, Repair and System Maintenance | 10% | ~13 |
| Domain 7: Human Factors That Impact Endoscope Systems | 8% | ~10 |
Practice your questions in this same proportion. If your question bank has 100 items, roughly 32 of them should cover Domain 4 topics. Candidates who practice evenly across all domains are systematically under-preparing for what the exam actually emphasizes.
For a complete breakdown of every content area, read our CER Exam Domains 2026: Complete Guide to All 7 Content Areas.
High-Yield Topics by Domain
Not every topic within a domain carries equal weight. Based on the content outline, certain subjects appear repeatedly in practice scenarios and are worth drilling more aggressively.
Domain 1: Microbiology and Infection Control (12%)
Questions test understanding of how pathogens survive on endoscope surfaces and how infection chain-of-transmission principles apply to reprocessing failures.
- Spaulding classification (critical, semi-critical, non-critical) and where endoscopes fall
- Biofilm formation timelines and why immediate post-procedure cleaning matters
- Modes of transmission relevant to flexible endoscopy
- Standard and transmission-based precautions in the reprocessing environment
Domain 4: Endoscope Processing Steps (32%)
This is the largest domain-roughly 40 of your 125 scored questions. Every step in the reprocessing sequence is fair game, and questions are heavily scenario-based.
- Pre-cleaning and point-of-use treatment immediately after a procedure
- Leak testing protocols and what a failed test requires
- Manual cleaning: brush selection, channel flushing, enzymatic detergent dilution and contact time
- High-level disinfection (HLD): chemical concentrations, temperature parameters, exposure times, MEC testing
- Automated endoscope reprocessors (AERs): loading, cycle validation, and failure responses
- Drying and alcohol flushing to prevent residual moisture
Deep preparation for Domain 4 alone could be the deciding factor in a passing score. Our dedicated CER Domain 4: Endoscope Processing Steps (32%) - Complete Study Guide 2026 covers every subtopic in this domain.
Domain 5: Endoscope Handling, Transport and Storage (16%)
The second-largest domain. Questions often focus on what can go wrong after reprocessing is complete-contamination during transport or improper storage conditions.
- Hang-dry storage vs. dry cabinet requirements
- Maximum storage hang time and factors that reset the clock
- Transport containers: clean vs. soiled, labeling requirements
- Coiling and positioning during transport to prevent damage
Domain 3: Work Area Design (12%)
Questions test whether candidates understand the physical and environmental requirements of the reprocessing suite, including ventilation, directional workflow, and sink specifications.
- Negative-pressure ventilation requirements in decontamination areas
- Soiled-to-clean unidirectional traffic flow principles
- Sink dimensions and dedicated-use requirements
- Personal protective equipment (PPE) requirements by work area zone
Additional domain-specific guides are available for CER Domain 1: Microbiology and Infection Control, CER Domain 2: Endoscope Purpose, Design and Structure, CER Domain 3: Work Area Design, CER Domain 5: Endoscope Handling, Transport and Storage, CER Domain 6: Endoscope Tracking, Repair and System Maintenance, and CER Domain 7: Human Factors That Impact Endoscope Systems.
Sample Practice Questions with Rationales
The following sample items illustrate the scenario-based format you will encounter. Study the rationales carefully-they model the reasoning the exam rewards.
Sample Question 1 - Domain 4
A technician is manually cleaning a gastrointestinal endoscope and notices the brush exits the biopsy channel with visible debris on the third pass. What is the correct next action?
- Proceed to high-level disinfection, as three passes exceed minimum requirements
- Continue brushing the channel until the brush exits visibly clean
- Place the scope in the AER immediately to address remaining contamination
- Soak the scope in enzymatic detergent for an additional 10 minutes without further brushing
Correct Answer: B. Manual cleaning must continue until the brush exits free of visible debris. Automated reprocessing is not a substitute for adequate manual cleaning, and a fixed number of passes does not guarantee cleanliness.
Sample Question 2 - Domain 1
Which characteristic of biofilm makes endoscope reprocessing particularly challenging?
- Biofilm forms only on external surfaces and can be removed with a single wipe
- Biofilm microorganisms are encased in a protective matrix that reduces chemical penetration
- Biofilm is destroyed immediately upon exposure to water at any temperature
- Biofilm formation requires more than 48 hours to begin on endoscope channels
Correct Answer: B. Biofilm embeds organisms in an extracellular matrix that significantly reduces the efficacy of disinfectants. This is why prompt pre-cleaning before biofilm can establish itself is a foundational principle of endoscope reprocessing.
Sample Question 3 - Domain 5
A reprocessed duodenoscope was stored hanging in a drying cabinet. Staff discover the cabinet door was left ajar overnight. What is the appropriate response?
- Visually inspect the scope and return it to service if no visible contamination is present
- Reprocess the scope from the beginning of the manual cleaning step
- Perform only high-level disinfection before returning the scope to use
- Document the event and quarantine the scope pending supervisor review only
Correct Answer: B. A compromised storage environment invalidates the reprocessing outcome. The scope must be fully reprocessed, beginning with manual cleaning, before it can be considered safe for patient use.
Key Takeaway
Notice that every sample question above presents a realistic scenario requiring a judgment call-not a vocabulary definition. Build your practice sessions around questions written in this style. Generic flashcard-style recall questions will not adequately prepare you for what HSPA actually tests.
Access a full bank of scenario-based questions at CER Exam Prep's free practice tests, built to match the May 2022 content outline domain weights.
The 25 Unscored Questions: What They Mean for You
Of the 150 questions on the exam, 25 are unscored pretest items that HSPA uses to evaluate new questions for future exam versions. You will not be told which questions are unscored, and they are distributed randomly throughout the exam.
The 3-hour time limit gives you roughly 72 seconds per question across all 150 items. In practice, most candidates complete the exam without running out of time, but the time pressure increases significantly if you revisit many flagged questions at the end. Practice under timed conditions from the start of your preparation, not just in the final days before your exam date.
A CER-Specific Practice Schedule
A four-week focused practice plan built around the domain weights-not generic exam advice-looks like this:
Foundation: Domains 1, 2, and 3
- Complete 20-30 practice questions on microbiology and infection control (Domain 1)
- Review endoscope anatomy and channel architecture (Domain 2) with labeled diagrams
- Study work area ventilation, flow, and PPE requirements (Domain 3)
- Goal: establish the environmental and biological context that underpins all processing decisions
Core Focus: Domain 4, Part 1 - Manual Steps
- Complete 40-50 practice questions on pre-cleaning, leak testing, and manual cleaning
- Drill enzymatic detergent parameters: dilution ratios, contact times, water temperature ranges
- Practice answering scenario questions where a single step is performed incorrectly
Core Focus: Domain 4, Part 2 - HLD, AERs, and Drying + Domain 5
- Complete 40-50 practice questions on HLD chemical parameters, MEC testing, and AER operation
- Shift to Domain 5: storage duration, drying cabinet requirements, transport protocols
- Review what constitutes a reprocessing failure and what triggers a patient notification process
Domains 6 and 7 + Full Timed Practice Exams
- Complete targeted questions on tracking systems, repair triage, and quality indicators (Domain 6)
- Review human factors: staffing ratios, fatigue, competency documentation (Domain 7)
- Complete at least two full 125-question timed practice exams under Prometric-like conditions
- Review every incorrect answer with a written rationale-not just the correct option
For a comprehensive study roadmap including resource recommendations, see our CER Study Guide 2026: How to Pass on Your First Attempt. For timing and preparation around exam day logistics, CER Exam Day Tips: 15 Strategies to Maximize Your Score covers what to do the morning of your Prometric appointment.
How the CER Is Scored
HSPA uses a criterion-referenced passing standard determined through the Angoff and Beuk methods. In practice, this means a panel of subject-matter experts evaluates each question and estimates the minimum knowledge level a competent entry-level endoscope reprocessor should possess. The resulting cut score is not published as a public percentage.
What this means for your practice strategy: do not target an arbitrary number like "score 75% and you pass." Instead, focus on whether you can correctly reason through clinical scenarios across all seven domains. Consistent performance across domain-representative question sets is a far better signal of readiness than hitting a self-imposed percentage threshold on a single practice exam.
For full details on what the exam costs including prep materials and renewal, see CER Certification Cost 2026: Complete Pricing Breakdown. Annual renewal requires 6 endoscope-reprocessing CE credits plus the HSPA renewal fee-details are covered in our CER Recertification 2026: Requirements, Costs & Timeline guide.
Ready to test your knowledge right now? Start a free CER practice exam aligned to the May 2022 content outline.
Frequently Asked Questions
125 of the 150 questions are scored. The remaining 25 are unscored pretest items used for future exam development. Because you cannot identify which questions are unscored, treat every question as if it counts toward your result.
Domain 4: Endoscope Processing Steps at 32% is by far the largest and most heavily tested domain, accounting for roughly 40 of your 125 scored questions. Domain 5 (16%) and Domains 1 and 3 (12% each) round out the top tier. Your practice question volume should mirror these weights.
HSPA does not publish a numeric cut score. The passing standard is set through the Angoff/Beuk criterion-referenced method, which evaluates what a minimally competent entry-level reprocessor should know. Focus on consistent, correct reasoning across all domains rather than targeting a specific percentage.
No. The CRCST is not a prerequisite for the CER. You need only 3 months of documented hands-on endoscope reprocessing experience. The CER is a standalone credential offered by HSPA for professionals specializing specifically in endoscope reprocessing.
You have 3 hours to complete the exam. Testing is computer-based at a Prometric center, and the exam is closed book. A tutorial is provided before the test begins. Review tools within the testing platform allow you to flag questions and return to them before submitting your final answers.
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