FREE CER Study Guide 2026: The HSPA Endoscope Reprocessor Walkthrough

This free CER study guide walks through the highest-yield content the HSPA Certified Endoscope Reprocessor (CER) exam tests, organized by the seven content areas of the official HSPA CER content outline — Endoscope Processing Steps; Endoscope Handling, Transport & Storage; Microbiology & Infection Control; Work Area Design; Endoscope Purpose, Design & Structure; Endoscope Tracking, Repair & System Maintenance; and Human Factors.^[1]

It is built to teach, not just describe: every content area has the real flexible-endoscope reprocessing science — leak testing, channel brushing, high-level disinfection chemistry, forced-air drying — plus worked exam-style scenarios, comparison tables, labeled diagrams, and built-in flashcards, taught the way the CER is actually tested against ANSI/AAMI ST91. The job of an endoscope reprocessor is to make sure a delicate, hard-to-clean scope is cleaned, disinfected, dried, and stored so it is genuinely safe for the next patient.

Read it content area by content area, then round out your prep with our practice questions and flashcards. The CER is awarded by HSPA, the body formerly known as IAHCSMM. If you also process general surgical instruments, pair this with our CRCST study guide— the CRCST is HSPA’s broad sterile processing exam, while the CER is the flexible-endoscope specialty.

CER Exam Snapshot

Endoscope Processing Steps is by far the largest area — 32% of the exam, so the point-of-use-treatment-through-drying workflow is where you earn the most points.^[1] Handling, Transport & Storage adds another 16%, so together the hands-on reprocessing-and-storage workflow is nearly half the exam. Weight your study there first, then build out the supporting science.

Percentages are each area’s share of the scored items, from the official May-2022 CER content outline.^[1] This guide teaches all seven areas as seven study modules, so the structure matches the CER content outline exactly.

How the CER Exam Is Built

The CER follows the HSPA content outline, built from a job analysis of working endoscope reprocessors, which groups every scored item into seven content areas. This guide teaches all seven as study modules, leading with the reprocessing workflow because it is both the largest area and the spine the rest of the exam supports.^[1]

• Endoscope Processing Steps (32%) — point-of-use treatment, leak testing, manual cleaning, high-level disinfection and sterilization, final rinse, and forced-air drying.
• Endoscope Handling, Transport & Storage (16%) — soiled and clean transport, drying and storage cabinets, event-related sterility, and maximum storage time.
• Microbiology & Infection Control (12%) — the Spaulding classification, microbial resistance, biofilm and bioburden, standard precautions, and the chain of infection.
• Work Area Design (12%) — unidirectional workflow, room separation, air pressure and changes, humidity, the three-sink decontamination room, and safety design.
• Endoscope Purpose, Design & Structure (10%) — scope types and purpose, the control head and insertion tube, the distal tip, and the channels and elevator.
• Endoscope Tracking, Repair & System Maintenance (10%) — traceability, unique identifiers, repair and return to service, and preventive maintenance.
• Human Factors That Impact Endoscope Systems (8%) — fatigue, interruptions, production pressure, competency, job aids, and just culture.

Endoscope Processing Steps

Endoscope Processing Steps is 32% of the exam — by far the largest content area and the heart of the job.^[1] It is the one-way ST91 sequence that takes a soiled scope to a patient-ready one: point-of-use treatment, leak testing, manual cleaning, high-level disinfection (or sterilization), final rinse, and drying.

Point-of-Use Treatment & Leak Testing

Reprocessing begins at the bedside. Point-of-use treatment — wiping the insertion tube and flushing the air, water, and suction channels immediately after the procedure — keeps organic soil moist and removes gross debris before it can dry.

Dried soil hardens and forms biofilm that downstream cleaning struggles to remove, so this first step protects every step that follows. The scope is then transported to decontamination in a closed, leak-proof, biohazard-labeled container.^[2]

Before the scope is ever immersed, it is leak tested: the scope is pressurized and the bending sectionangulated in all directions while a technician watches for a continuous stream of bubbles. A pinhole, crack, or torn channel lets fluid invade the scope’s internal components, causing costly damage and creating a reservoir that cannot be disinfected. A scope that fails the leak test is removed from service and sent for repair.^[2]

Manual Cleaning & Inspection

Manual cleaning is the single most critical reprocessing step. Every accessible channel is brushed along its full length with a correctly sized single-use brush, passed fully through until the bristles exit visibly clean, and flushed with freshly prepared enzymatic detergent that breaks down blood, mucus, and protein.

Brushing provides mechanical action that flushing alone cannot — it dislodges adherent soil and developing biofilm. A frayed brush is removed from service, and brushes are discarded after one scope.^[2]

After cleaning, the scope is inspected under lighted magnification — and inside the channels with a borescope — for residual soil, moisture, scratches, or peeling coating. Anything found means cleaning is not complete: the scope goes back for re-cleaning before any disinfection. An AER does not replace this manual work; thorough manual cleaning must be completed first.^[2]

High-Level Disinfection & Sterilization

Because a flexible endoscope is a semicritical device, high-level disinfection (HLD) — a process that destroys all microorganisms except large numbers of bacterial spores — is the minimum acceptable endpoint, with sterilization preferred when the scope enters a sterile site. Common high-level disinfectants are OPA (no activation, shorter contact time, less respiratory irritation), glutaraldehyde (usually activated and verified, with irritating vapors), and peracetic acid (sporicidal).^[3]

Three things govern a reliable HLD: the right contact time, temperature, and concentration per the IFU; a passing MEC test before each use of a reusable disinfectant (the MEC result, not the printed date, decides whether the solution may be used); and full contact with every internal surface — in manual HLD, all channels are filled and air bubbles are purged so no area is left untreated. Scopes that enter a sterile body cavity are sterilized, typically by a low-temperature method such as ethylene oxide or vaporized hydrogen peroxide, because steam would damage the heat-sensitive materials.^[2]

Final Rinse & Drying

After disinfection, the scope receives a final rinsewith sterile water or, at minimum, bacteria-free filtered water (often through a 0.1–0.2 micron filter) to remove disinfectant residue that could injure the patient’s mucosa and to flush away loosened debris. Then comes the step the CER tests relentlessly: forced-air drying.^[2]

ST91 calls for drying channels with pressure-regulated instrument-grade (or at least HEPA-filtered) air for at least about 10 minutes, until no visible moisture remains. Drying is infection control: residual moisture lets waterborne Pseudomonas aeruginosa multiply and form biofilm during storage, undoing a perfect disinfection. The air must be pressure-regulated to the IFU, because excessive pressure can rupture the delicate channels; if an alcohol flush is used, it is purged through with air rather than left to evaporate.^[2]

AERs & Cleaning Verification

An Automated Endoscope Reprocessor (AER) automates disinfectant exposure, rinsing, and channel perfusion with documented, repeatable parameters, reducing human error — but it does not eliminate manual cleaning, which must be completed first. If a channel-irrigation connector pops loose during a cycle, that channel is treated as inadequately processed and the scope is reprocessed through a full cycle.^[2]

Cleaning verification proves the cleaning actually worked: lighted-magnification and borescope inspection for retained soil and damage, and objective tests such as ATP bioluminescence that measure residual organic material. Each HLD cycle is documented — the scope identifier, the disinfectant lot and MEC result, the operator, and the date and parameters — for traceability.^[2]

Microbiology & Infection Control

Microbiology & Infection Control is 12% of the exam.^[1] It is the science behind every reprocessing decision: which organisms are hardest to kill, why cleaning must precede disinfection, and how the whole workflow interrupts the spread of infection.

Spaulding Classification

The Spaulding classification, from the CDC guideline, ranks every device by infection risk based on how it contacts the patient, and that risk sets the required reprocessing level. Critical items enter sterile tissue and must be sterilized; semicritical items touch mucous membranes or non-intact skin and need high-level disinfection at minimum; noncritical items touch only intact skin. Because a flexible GI endoscope normally contacts mucous membranes, it is a semicritical device — the single most important classification fact on this exam.^[3]

Microbial Resistance, Biofilm & Bioburden

Organisms differ in how hard they are to kill. On the resistance hierarchy, bacterial endospores (Bacillus, Clostridioides) are generally the most resistant to chemical inactivation, which is why they are the benchmark for sterilization.

Mycobacteria resist disinfection because of a waxy, lipid-rich cell wall, so HLD agents are timed to achieve mycobactericidal kill. Bioburden — the number of viable microbes on a device before reprocessing — must be lowered by thorough cleaning so disinfection can succeed.^[3]

Biofilm is the reprocessor’s nemesis: a community of microbes in a self-produced protective matrix that forms when soil is left to dry in a channel. The long, narrow channels of a flexible endoscope retain moisture and soil and are hard to access, so they are especially biofilm-prone — and once mature, biofilm resists routine cleaning and disinfection. The strategy is prevention (point-of-use treatment, prompt cleaning), not removal after the fact.^[3]

Standard Precautions & the Chain of Infection

Standard precautions apply to every patient regardless of known infection status: treat all blood and body fluids as potentially infectious and wear appropriate PPE in the decontamination area. The chain of infection — infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host — must be intact for infection to spread; properly reprocessing a scope removes the device as a reservoir, breaking the chain.^[3]

Endoscope Purpose, Design & Structure

Endoscope Purpose, Design & Structure is 10% of the exam.^[1] You cannot reprocess a scope you do not understand — the design is what makes endoscopes uniquely hard to clean, and the channels and elevator are exactly where infections hide.

Scope Types & Purpose

Flexible endoscopes are named for where they go: a gastroscope is shorter for the upper GI tract; a colonoscope is longer to traverse the entire large intestine; a bronchoscope examines the airways; and a duodenoscope is a side-viewing scope with an elevator at the tip, used mainly for ERCP. Because they combine long, narrow, sometimes branching lumens with heat-sensitive plastics and optics that cannot tolerate steam, flexible scopes are inherently harder to clean than most surgical instruments — and must be reprocessed by HLD or low-temperature methods, not steam.^[4]

Components & Anatomy

The control head holds the angulation knobs and the seats for the suction and air/water valves, plus the entry to the working channel. The insertion tube is the long flexible shaft advanced into the patient, carrying the channels and imaging bundle to the tip; the bending (angulation) section just behind the tip steers it up, down, left, and right. The distal tip presents the objective lens, light-guide lens(es), air/water nozzle, and the working/suction channel opening — each inspected and cleaned because debris there blocks visualization and harbors microbes.^[2]

Channels & the Elevator

Channel configuration varies by model — air/water, suction/working, auxiliary water, and, on duodenoscopes, the elevator channel — so reprocessing must follow the model-specific IFU. The working channel is the top cleaning priority because accessories pass through it and suction is applied, so it directly contacts patient fluids and must be brushed along its full length. The elevator on a duodenoscope is the highest-risk feature: its recessed location traps soil and shields microbes, which is why it has been linked to outbreaks and demands extra manual cleaning per the IFU.^[4]

Detachable accessories — the air/water valve, suction valve, and biopsy-port cap — are removed and cleaned separately, then disinfected or sterilized per their own IFU, and kept identified with their scope so a complete, traceable assembly is ready for use.^[2]

Work Area Design

Work Area Design is 12% of the exam.^[1] The room itself is an infection-control tool: its layout, airflow, and pressures keep contamination contained and clean scopes clean.

Unidirectional Workflow & Room Separation

The processing area is built around unidirectional workflow: scopes move one way — soiled receipt, cleaning, disinfection, drying, storage — and never travel back against the dirty-to-clean current. ST91 prefers decontamination and high-level disinfection in two physically separate rooms to reduce recontamination; where only one room is feasible, a closable pass-through window moves items from the dirty side to the clean side while maintaining separation. Soiled and clean surfaces are never shared.^[2]

Pressure, Air Changes & Humidity

The decontamination room is kept at negative pressure so air flows inward and the aerosols and chemical vapors from cleaning are contained, with a minimum of 6 air changes per hour. The clean workroom is kept at positive pressure so contaminated air cannot enter, with a minimum of 4 air changes per hour.

Both areas are held at a maximum of 60% relative humidity and roughly 60–73°F. These parameters come from ANSI/ASHRAE/ASHE Standard 170, as referenced by ST91, and the containment performance is monitored over time.^[2]

Sinks, Eyewash & Safety Design

ST91 describes an ideal decontamination room with three dedicated sinks — for leak testing, manual cleaning, and critical rinsing — to keep the workflow orderly and reduce cross-contamination. Because manual cleaning uses irritant chemicals, an emergency eyewash station must be reachable within about 10 seconds of unobstructed travel. Chemicals are kept in ventilated, labeled storage, and storage cabinets are sited at least 3 feet from any sink so splash and aerosols cannot recontaminate clean, dry scopes.^[2]

Endoscope Handling, Transport & Storage

Endoscope Handling, Transport & Storage is 16% of the exam — the second-largest area.^[1] A perfectly disinfected scope can still be ruined by wet storage, contact damage, or careless transport, so this area is about keeping a patient-ready scope ready.

Transport of Soiled & Clean Scopes

A soiled scope is transported in a closed, rigid, leak-proof, puncture-resistant container labeled as biohazard, with the insertion tube laid in wide, loose loops without sharp kinks to protect the internal channels and fiber bundles. After it holds a soiled scope, the container is contaminated and must be reprocessed before it can carry a clean one. A clean, reprocessed scope is delivered in a clean, covered container or cart, separated from soiled items.^[5]

Drying Cabinets & Storage

A high-level-disinfected scope is stored hanging vertically, distal tip down, in a clean, controlled drying/storage cabinet that circulates HEPA-filtered air. Hanging straight and free of contact with walls, shelves, and neighboring scopes lets channels drain and prevents abrasion and trapped moisture.

The cabinet must be tall enough for the scope’s full extended length so the tip never rests on the floor. An active drying cabinet keeps drying the lumens; a conventional cabinet does not, so channels must be fully force-dried first. The classic failure organism is Pseudomonas aeruginosa, which thrives in retained moisture.^[2]

Event-Related Sterility & Maximum Storage Time

How a stored scope is governed depends on its endpoint. A terminally sterilized scope kept in an intact sterile barrier package follows event-related sterility: it stays ready for use until an event — a tear, wetting, or broken seal — compromises the package, not until a calendar date.

A high-level-disinfected scope hangs unwrapped, and its maximum storage time (hang time) before it must be reprocessed is set by a facility multidisciplinary risk assessment, with transport and storage conditions as inputs. A scope removed from the cabinet and handled — even if the case is canceled — is reprocessed before storage or use.^[2]

Endoscope Tracking, Repair & System Maintenance

Endoscope Tracking, Repair & System Maintenance is 10% of the exam.^[1] It is how a facility proves a scope was safe for a given patient, keeps the fleet working, and responds when something goes wrong.

Traceability & Unique Identifiers

Traceability links each specific scope to the patient and procedure, the reprocessing method and equipment, and the staff member who processed it — so a recall (lookback) can identify every exposed patient if a reprocessing or HLD failure is later discovered. This requires a unique identifier per scope, not just a model number, so identical scopes can be told apart. A missing leak test or cleaning-verification record for a cycle compromises the facility’s ability to confirm the scope was safe for that patient and to defend the cycle in an investigation.^[2]

Repair & Return to Service

A scope that fails a leak test or shows internal damage on borescope inspection — scratches, peeling coating, retained debris — is removed from service. When a scope returns from repair, the repair details are logged and the scope is reprocessed and leak tested per IFU before it re-enters clinical use. Borrowed loanerscopes are tracked under a unique identifier with full reprocessing and patient-use records, just like owned scopes, and original-equipment (OEM) parts are used to preserve the scope’s validated performance.^[2]

Preventive Maintenance & Borescope Inspection

Preventive maintenance is proactive, manufacturer-specified servicing and inspection at defined intervals — catching wear before failures occur — rather than reactive repair after a scope breaks. Borescope inspection of internal channels is recommended by ST91, but each facility sets its frequency as part of its quality program. A function check after reprocessing confirms the scope operates correctly and is safe for patient use before storage.^[2]

Human Factors That Impact Endoscope Systems

Human Factors That Impact Endoscope Systems is 8% of the exam.^[1] Reprocessing is a long chain of sequential steps held partly in working memory, so the conditions a technician works under directly determine whether every step gets done.

Fatigue, Interruptions & Production Pressure

Human factors are the leading source of reprocessing error. Fatigue late in a long shift reduces vigilance and makes a technician more likely to skip a step such as visual inspection — which is a patient-safety issue, not just a comfort one, because a skipped step leaves residual soil or inadequate disinfection on a scope used on the next patient.

Interruptions and distractions (phone calls, foot traffic) cause a technician to lose place in the sequence and omit a step like channel brushing. Production pressure — quotas that exceed what careful processing allows — pushes staff to shortcut time-dependent steps. Heavy, hot PPE and high cognitive load add to the risk.^[2]

Competency, Job Aids & Just Culture

The defenses are designed in. Competency is verified for each specific scope make and model and its connectors and cleaning-verification procedures — a written test is not enough; a documented hands-on assessment on that model comes before independent processing.

Pictorial job aids posted at the sink lower memory demand with in-context cues; standardized nomenclature removes ambiguity; and a buddy-check adds a redundant second look at critical steps. A just culture responds to an error by fixing the system conditions that allowed it while coaching the individual, which supports honest reporting of near-misses.^[2]

How to Use This Study Guide

Work through the guide one content area at a time, leading with the reprocessing workflow. After each area, check it off in the contents to raise your exam-readiness score, then drill the same content in our free practice questions and flashcards — active recall and timed practice are what move knowledge into exam-day performance.

• Weight your time by the percentages. Processing Steps (32%) plus Handling, Transport & Storage (16%) are nearly half the exam. Start there.
• Make the reprocessing order automatic. Point-of-use → leak test → manual cleaning → inspection → HLD → rinse → dry → store. Cleaning always before disinfection.
• Know the HLD details cold. OPA vs glutaraldehyde, MEC before each use, contact time/temperature/concentration, and full-channel contact.
• Respect drying. Forced-air drying for ~10 minutes, why a wet scope grows Pseudomonas — drying is infection control.
• Then prove it. When a content area feels easy, confirm it with our practice questions and flashcards.

Common questions CER candidates search and get asked — each answered briefly and backed by an official source (HSPA, ANSI/AAMI ST91, CDC, FDA, or OSHA). Tap any card to test yourself.

CER Glossary

Key flexible-endoscope reprocessing terms in one place. Hover any dotted term throughout the guide for its definition; the full list is below.

CER

Certified Endoscope Reprocessor — the HSPA credential for a technician who reprocesses flexible and semi-rigid endoscopes.

HSPA

Healthcare Sterile Processing Association — the certifying body for the CER, formerly IAHCSMM (renamed January 1, 2022).

flexible endoscope

A long, flexible instrument with internal channels and optics used to view and treat inside the body (e.g., a colonoscope or gastroscope); a semicritical device.

ST91

ANSI/AAMI ST91:2021 — the comprehensive standard for processing flexible and semi-rigid endoscopes in health care facilities; the primary CER reference.

Spaulding classification

A framework that ranks devices as critical, semicritical, or noncritical by infection risk to set the required reprocessing level.

critical

A device that enters sterile tissue or the vascular system — must be sterilized.

semicritical

A device that contacts intact mucous membranes or non-intact skin — needs high-level disinfection at minimum (e.g., a flexible endoscope).

noncritical

A device or surface that contacts only intact skin — needs low- or intermediate-level disinfection.

high-level disinfection

A process (HLD) that destroys all microorganisms except large numbers of bacterial spores; the minimum endpoint for a flexible endoscope.

sterilization

A validated process that destroys ALL microbial life, including bacterial spores; preferred for scopes entering a sterile site.

bioburden

The number of viable microorganisms on a device before reprocessing.

biofilm

A community of microbes embedded in a self-produced protective matrix that forms when soil dries in a channel; it resists cleaning and disinfection.

point-of-use treatment

Bedside pre-cleaning right after the procedure — wipe the insertion tube and flush channels — so soil stays moist and does not dry.

leak test

A pressurized check for breaches in a scope's fluid-tight barrier, performed before the scope is immersed in cleaning solution.

manual cleaning

Brushing every accessible channel and flushing with enzymatic detergent to remove organic soil; the most critical reprocessing step.

enzymatic detergent

A cleaner whose enzymes break down blood, mucus, and protein; generally not antimicrobial, so it is freshly prepared and discarded each scope.

glutaraldehyde

A high-level disinfectant that usually requires activation and concentration verification; its vapors irritate the eyes and airways.

OPA

Ortho-phthalaldehyde — a high-level disinfectant (0.55%) that needs no activation, has a shorter contact time, and causes less respiratory irritation.

peracetic acid

A sporicidal liquid chemical agent used for high-level disinfection or liquid chemical sterilization of immersible endoscopes.

MEC

Minimum Effective Concentration — the lowest concentration at which a reusable high-level disinfectant still works, verified before each use with a test strip.

contact time

The validated exposure time at the labeled concentration and temperature that achieves a disinfectant's claimed microbial kill.

AER

Automated Endoscope Reprocessor — a machine that automates disinfectant exposure, rinsing, and channel perfusion; manual cleaning must still be done first.

borescope

A thin lighted scope used to inspect inside endoscope channels for retained soil, scratches, or peeling coating that surface inspection cannot reveal.

forced-air drying

Drying channels with pressure-regulated instrument-grade or HEPA-filtered air (≥ ~10 minutes) so no moisture remains before storage.

Pseudomonas aeruginosa

A waterborne organism that thrives in moisture and biofilm — classically linked to inadequately dried scopes and contaminated rinse water.

duodenoscope

A side-viewing flexible endoscope with a movable elevator at the distal tip, used mainly for ERCP; its elevator recess is hard to clean.

elevator

A movable forceps raiser at the distal tip of a duodenoscope that aims accessories; its recess traps soil and needs extra cleaning per IFU.

working channel

The lumen through which accessories pass and suction is applied; heavily contaminated, it must be brushed along its full length.

insertion tube

The long flexible shaft advanced into the patient that carries the channels and the imaging bundle to the distal tip.

control head

The handle section housing the angulation knobs and the seats for the suction and air/water valves, plus the working-channel entry.

event-related sterility

The standard that a sterilized, packaged scope stays sterile until an event compromises the package — not until a calendar date.

maximum storage time

The hang time a processed scope may be stored before reprocessing, set by a facility multidisciplinary risk assessment.

drying/storage cabinet

A cabinet that stores scopes hanging vertically in HEPA-filtered air; an active cabinet also force-dries the lumens.

IFU

Instructions For Use — the manufacturer's validated, FDA-cleared method for reprocessing a specific device; legally binding and model-specific.

traceability

Linking each specific scope to the patient, procedure, reprocessing method, and staff so a recall (lookback) can identify exposed patients.

unique identifier

A per-scope identifier (not just a model number) that distinguishes identical scopes for use, reprocessing, repair, and recall.

preventive maintenance

Proactive, manufacturer-specified servicing and inspection at defined intervals to catch wear before a scope fails.

human factors

How workload, fatigue, interruptions, workspace design, and culture affect a technician's ability to perform every reprocessing step correctly.

standard precautions

Infection-control practices applied to all patients — treat all blood and body fluids as infectious and wear appropriate PPE.

CER Study Guide FAQ

References

1. 1.Healthcare Sterile Processing Association (HSPA). “Certified Endoscope Reprocessor (CER) Certification Overview & Content Outline (May 2022).” HSPA. ↑
2. 2.Association for the Advancement of Medical Instrumentation (AAMI). “ANSI/AAMI ST91:2021 — Flexible and Semi-Rigid Endoscope Processing in Health Care Facilities.” AAMI. ↑
3. 3.Centers for Disease Control and Prevention (CDC). “Guideline for Disinfection and Sterilization in Healthcare Facilities (2008, updated).” CDC. ↑
4. 4.U.S. Food and Drug Administration (FDA). “Reprocessing of Reusable Medical Devices & Duodenoscope Reprocessing Guidance.” FDA. ↑
5. 5.Occupational Safety and Health Administration (OSHA). “Bloodborne Pathogens Standard (29 CFR 1910.1030) & Hazard Communication.” OSHA. ↑
6. 101.Centers for Disease Control and Prevention (CDC). “Guideline for Disinfection and Sterilization in Healthcare Facilities (Spaulding classification).” cdc.gov, accessed 20 June 2026. ↑
7. 102.U.S. Food and Drug Administration (FDA). “Infections Associated with Reprocessed Duodenoscopes.” fda.gov, accessed 20 June 2026. ↑

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