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How to perform endoscope leak testing

Cases where endoscope internal water ingress occurs due to negligence in leak testing operations, further resulting in circuit board corrosion, optical system damage and even bacterial biofilm formation, still happen frequently in various endoscopy centers. These issues not only lead to high maintenance costs, but also may become potential sources of cross-infection.

Based on practical clinical operation experience, this article systematically sorts out the standardized operating procedures for the two mainstream leak testing devices: handheld and air pump types, providing an implementable and quality-controllable technical reference for endoscope cleaning and disinfection teams.

1. Clinical Significance and Preconditions of Endoscope Leak Testing

Essentially, endoscope leak testing is performed before the cleaning and disinfection process. A certain pressure of air is injected into the internal channels of the endoscope, which is then fully immersed in water. By observing whether continuous air bubbles escape, the integrity of the endoscope’s outer surface and internal lumens can be assessed.

This procedure is critical for detecting leakage points before water penetrates into the endoscope. Once water enters the device, core components including the circuit system, optical system and bending rubber will suffer irreversible damage in a short time. In addition, once bacterial biofilms form in tiny cracks, they cannot be easily removed by routine cleaning and disinfection procedures, posing a direct threat to the diagnosis and treatment safety of subsequent patients.

Standardized leak testing shall be implemented as a mandatory step in the first daily cleaning cycle. Operators are required to have a basic understanding of equipment structure and the ability to perform all procedures in full compliance with standardized protocols.

2. Introduction and Operating Procedure of the Manual Leak Tester

Featuring portability, no power requirement and ready-to-use convenience, the handheld leak tester remains the preferred tool for many primary medical institutions and emergency endoscopy scenarios. However, its operation heavily relies on standardized performance by operators, and any oversight in any step may compromise detection accuracy.

Medical pressure gauge with inflatable bulb and tube.

Step 1: Connect the adapterAlign the connector of the leak tester adapter with the endoscope ventilation port, press moderately, and then rotate clockwise to the locked position. Ensure firm connection to prevent disconnection during pressurization or water immersion.

Step 2: Check the pressure relief knob. Verify that the pressure relief knob on the main body of the leak tester is fully closed. This is a prerequisite for building test pressure; omitting this step commonly results in failure to pressurize normally.

Step 3: Manually pressurize to the standard range. Continuously squeeze the hand pump and observe the pressure gauge needle. The standard test pressure range is 19–27 kPa, corresponding to the green zone on the dial. To reliably detect micro leaks and slight water seepage, it is clinically recommended to stabilize the pressure at 27 kPa. Allow several seconds of static time after pressurization until the pressure stabilizes before proceeding.

Step 4: Fully immerse for inspection
Submerge the endoscope connected to the leak tester completely in room-temperature clean water or a dedicated test tank. Bend the endoscope’s bending section to its maximum angle and observe continuously for no less than 30 seconds. Key observation points: no continuous air bubbles emerging from the entire bending section, distal tip and insertion tube. Single scattered bubbles are mostly surface-attached air, which can be removed by gentle wiping before re-inspection.

Step 5: Take out the endoscope. After observation, lift the endoscope steadily out of the water to avoid pressure fluctuation or collision caused by violent shaking.

Step 6: Release pressure. Press the pressure release button on the leak tester to exhaust the air inside the endoscope channels smoothly. This step is mandatory; sudden pressure changes may impact the internal structure of the endoscope.

Step 7: Disconnect the leak tester. Rotate the adapter counterclockwise and remove it from the endoscope ventilation port. Avoid lateral force during operation to prevent damage to the interface sealing ring.

Step 8: Dry and store. Thoroughly wipe the surface and connectors of the leak tester with a clean soft cloth. Store it in the designated position for standby use only after complete drying.

3. Detailed Operation Guide for Electric Air Pump Leak Tester

Air pump leak testing devices, represented by the MU-1 series, automate the pressure build-up process, allowing operators to focus on the core observation procedures. Its procedural design reflects a more systematic quality control concept.

Pre-inspection: Waterproof Cap Dryness Check

Before connection, confirm that the inner side of the endoscope waterproof cap is completely dry. Any residual tiny moisture may be drawn into the endoscope after ventilation and cause adverse damage.

Device Connection and Self-Check

Connect the leak tester plug to the air pump and turn on the power. After confirming normal air output, attach the waterproof cap to the endoscope, then connect the leak tester adapter to the endoscope ventilation port. Check whether the rubber bladder on the leak tester inflates evenly, which serves as a direct indicator to judge connection tightness.

Immersion and Channel Venting

Fully submerge the endoscope in water. Use a syringe to inject water into the suction channel, water and air supply channels to exhaust residual air inside the lumens. This step prevents the original air inside the channels from being misjudged as leakage bubbles.

Systematic Zonal Inspection

This is the core step of air pump leak testing, which shall be completed in the following order:

Bending Section Inspection
Knob Section Inspection
Button Section Inspection

Closing Procedures

Upon completion of observation, take the endoscope out of water first, then turn off the main unit power supply. Finally, disconnect the leak tester connector and remove the waterproof cap in sequence. The operation order must not be reversed. Taking out the endoscope before powering off can effectively prevent water backflow and inhalation into the device interior.

4. Analysis on Clinical Applicability of the Two Leak Testing Methods

Handheld and air pump leak testers differ in operational logic, and medical institutions may select the appropriate type according to equipment allocation, staff training status, and practical application scenarios.

Advantages and Limitations of Handheld Leak Testers

Its greatest advantage is unrestricted by site conditions and available for immediate use at any time. However, the operator’s experience directly determines testing quality. Every step, including adequate pressurization, comprehensive observation and steady pressure relief, relies on the operator’s judgment. Newly recruited staff must receive systematic training before independent operation.

Advantages and Limitations of Air Pump Leak Testers

Air pump devices realize standardized pressure control, lower operational difficulty, and allow operators to focus more on visual inspection. The stepwise quality control design also facilitates operational assessment and quality traceability for managers. Nevertheless, such equipment requires regular calibration, as well as stable power supply and dedicated placement space.

Regardless of the equipment adopted, the core purpose of leak testing remains unified: to detect and locate any structural integrity defects before water ingress causes irreversible damage to the endoscope. A clear understanding of this goal helps operators maintain rigorous standards throughout every procedure.

Although handheld and air pump leak testing procedures vary, they share the same core principles: tight connection, proper pressure, comprehensive observation, and standardized operation. Internalizing standardized operations into daily habits reflects the professional competence of all endoscopy medical staff.

True professionalism lies in every standardized and repeatable operational detail. When leak testing evolves from a routine task into a quality-oriented work culture, a solid foundation for medical safety will be established.

The operating procedures described in this article are formulated in accordance with general clinical specifications. For specific implementation, please refer to the original manufacturer’s operation manual of the equipment used in your medical institution.

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