CERTIFIED ENDOSCOPE REPROCESSOR (CER) EXAM 2026
Updated Practice Questions Comprehensive Flexible Endoscope
Reprocessing Review • Detailed Explanations • Verified Answers •
Complete Success Workbook
Content Domain Weight
Microbiology & Infection Control ~18%
Endoscope Design and Function ~20%
Workflow & Processing Steps ~35%
Handling, Transport & Storage ~12%
Tracking & System Maintenance ~10%
Human Factors ~5%
DOMAIN 1: MICROBIOLOGY AND INFECTION CONTROL
QUESTION 1
Which link in the chain of infection is broken when a technician uses a single-use
brush to scrub an endoscope channel?
A) Portal of entry
B) Mode of transmission
C) Susceptible host
D) Reservoir
,RATIONALE:
Correct Answer: B) Mode of transmission
By cleaning the endoscope, the technician prevents the endoscope from acting as
a vehicle (mode) to transmit pathogens from one patient to another. The chain of
infection requires all six links to be present for transmission to occur: (1) infectious
agent, (2) reservoir, (3) portal of exit, (4) mode of transmission, (5) portal of entry,
and (6) susceptible host. Cleaning and disinfection break the mode of transmission
link by eliminating the pathogen's ability to travel from one patient to another via
the contaminated device.
Option A: Portal of entry refers to how the pathogen enters the host (e.g., mucous
membranes, broken skin).
Option C: Susceptible host refers to the patient at risk of infection.
Option D: Reservoir refers to the place where the pathogen lives and multiplies
(e.g., contaminated endoscope).
QUESTION 2
According to the Spaulding Classification, a flexible endoscope that enters a
mucous membrane is considered:
A) Critical
B) Semi-critical
C) Non-critical
D) High-risk
RATIONALE:
Correct Answer: B) Semi-critical
The Spaulding Classification categorizes patient-care items based on the risk of
infection transmission. Semi-critical items come into contact with mucous
membranes or non-intact skin and require at least high-level disinfection
(HLD) . Flexible endoscopes, which contact mucous membranes during
procedures such as colonoscopy and gastroscopy, fall into this category. Critical
,items penetrate soft tissue or bone and must be sterilized. Non-critical items
contact intact skin and require only low-level disinfection.
Option A: Critical items penetrate soft tissue or bone and require sterilization.
Option C: Non-critical items contact intact skin and require low-level disinfection.
Option D: "High-risk" is not a Spaulding classification category.
QUESTION 3
A multi-drug resistant organism (MDRO) frequently associated with contaminated
duodenoscopes is:
A) Methicillin-resistant Staphylococcus aureus (MRSA)
B) Carbapenem-resistant Enterobacteriaceae (CRE)
C) Vancomycin-resistant Enterococcus (VRE)
D) Clostridioides difficile
RATIONALE:
Correct Answer: B) Carbapenem-resistant Enterobacteriaceae (CRE)
CRE (Carbapenem-resistant Enterobacteriaceae) is a highly resistant pathogen
(MDRO) that has been linked to outbreaks involving complex endoscopes like
duodenoscopes. The elevator channel of duodenoscopes, which is difficult to clean
and disinfect, has been implicated in CRE transmission. CRE outbreaks have
driven the FDA, CDC, and professional bodies to demand specialized competency
in endoscope reprocessing.
Option A: MRSA is an MDRO but is more commonly associated with skin and
soft tissue infections.
Option C: VRE is an MDRO but is less frequently associated with endoscope-
related outbreaks.
Option D: C. difficile is associated with spore transmission and environmental
contamination.
QUESTION 4
, What is the primary purpose of bedside pre-cleaning immediately after an
endoscopic procedure?
A) To perform a manual leak test
B) To sterilize the insertion tube
C) To prevent the formation of biofilm and drying of organic soil
D) To test the fiber-optic light transmission
RATIONALE:
Correct Answer: C) To prevent the formation of biofilm and drying of
organic soil
Immediate pre-cleaning at the point of use prevents organic matter from drying and
forming a protective biofilm, which is much harder to remove later. Biofilm is a
complex community of microorganisms that produces a protective matrix, making
it resistant to disinfectants and sterilants. Bedside pre-cleaning is the first and most
critical step in the reprocessing workflow because dried soil can protect
microorganisms from subsequent disinfection or sterilization.
Option A: Leak testing occurs after pre-cleaning in the decontamination area.
Option B: Bedside pre-cleaning does not sterilize the endoscope.
Option D: Light transmission testing is unrelated to pre-cleaning.
QUESTION 5
In the reprocessing suite, the air pressure in the decontamination area should be:
A) Positive
B) Neutral
C) Negative
D) Equal to the HLD area
RATIONALE:
Correct Answer: C) Negative
Updated Practice Questions Comprehensive Flexible Endoscope
Reprocessing Review • Detailed Explanations • Verified Answers •
Complete Success Workbook
Content Domain Weight
Microbiology & Infection Control ~18%
Endoscope Design and Function ~20%
Workflow & Processing Steps ~35%
Handling, Transport & Storage ~12%
Tracking & System Maintenance ~10%
Human Factors ~5%
DOMAIN 1: MICROBIOLOGY AND INFECTION CONTROL
QUESTION 1
Which link in the chain of infection is broken when a technician uses a single-use
brush to scrub an endoscope channel?
A) Portal of entry
B) Mode of transmission
C) Susceptible host
D) Reservoir
,RATIONALE:
Correct Answer: B) Mode of transmission
By cleaning the endoscope, the technician prevents the endoscope from acting as
a vehicle (mode) to transmit pathogens from one patient to another. The chain of
infection requires all six links to be present for transmission to occur: (1) infectious
agent, (2) reservoir, (3) portal of exit, (4) mode of transmission, (5) portal of entry,
and (6) susceptible host. Cleaning and disinfection break the mode of transmission
link by eliminating the pathogen's ability to travel from one patient to another via
the contaminated device.
Option A: Portal of entry refers to how the pathogen enters the host (e.g., mucous
membranes, broken skin).
Option C: Susceptible host refers to the patient at risk of infection.
Option D: Reservoir refers to the place where the pathogen lives and multiplies
(e.g., contaminated endoscope).
QUESTION 2
According to the Spaulding Classification, a flexible endoscope that enters a
mucous membrane is considered:
A) Critical
B) Semi-critical
C) Non-critical
D) High-risk
RATIONALE:
Correct Answer: B) Semi-critical
The Spaulding Classification categorizes patient-care items based on the risk of
infection transmission. Semi-critical items come into contact with mucous
membranes or non-intact skin and require at least high-level disinfection
(HLD) . Flexible endoscopes, which contact mucous membranes during
procedures such as colonoscopy and gastroscopy, fall into this category. Critical
,items penetrate soft tissue or bone and must be sterilized. Non-critical items
contact intact skin and require only low-level disinfection.
Option A: Critical items penetrate soft tissue or bone and require sterilization.
Option C: Non-critical items contact intact skin and require low-level disinfection.
Option D: "High-risk" is not a Spaulding classification category.
QUESTION 3
A multi-drug resistant organism (MDRO) frequently associated with contaminated
duodenoscopes is:
A) Methicillin-resistant Staphylococcus aureus (MRSA)
B) Carbapenem-resistant Enterobacteriaceae (CRE)
C) Vancomycin-resistant Enterococcus (VRE)
D) Clostridioides difficile
RATIONALE:
Correct Answer: B) Carbapenem-resistant Enterobacteriaceae (CRE)
CRE (Carbapenem-resistant Enterobacteriaceae) is a highly resistant pathogen
(MDRO) that has been linked to outbreaks involving complex endoscopes like
duodenoscopes. The elevator channel of duodenoscopes, which is difficult to clean
and disinfect, has been implicated in CRE transmission. CRE outbreaks have
driven the FDA, CDC, and professional bodies to demand specialized competency
in endoscope reprocessing.
Option A: MRSA is an MDRO but is more commonly associated with skin and
soft tissue infections.
Option C: VRE is an MDRO but is less frequently associated with endoscope-
related outbreaks.
Option D: C. difficile is associated with spore transmission and environmental
contamination.
QUESTION 4
, What is the primary purpose of bedside pre-cleaning immediately after an
endoscopic procedure?
A) To perform a manual leak test
B) To sterilize the insertion tube
C) To prevent the formation of biofilm and drying of organic soil
D) To test the fiber-optic light transmission
RATIONALE:
Correct Answer: C) To prevent the formation of biofilm and drying of
organic soil
Immediate pre-cleaning at the point of use prevents organic matter from drying and
forming a protective biofilm, which is much harder to remove later. Biofilm is a
complex community of microorganisms that produces a protective matrix, making
it resistant to disinfectants and sterilants. Bedside pre-cleaning is the first and most
critical step in the reprocessing workflow because dried soil can protect
microorganisms from subsequent disinfection or sterilization.
Option A: Leak testing occurs after pre-cleaning in the decontamination area.
Option B: Bedside pre-cleaning does not sterilize the endoscope.
Option D: Light transmission testing is unrelated to pre-cleaning.
QUESTION 5
In the reprocessing suite, the air pressure in the decontamination area should be:
A) Positive
B) Neutral
C) Negative
D) Equal to the HLD area
RATIONALE:
Correct Answer: C) Negative
