Interrupted Sterilization Cycles: A Practical Hold-and-Investigate Framework

An interrupted sterilization cycle creates a release decision that cannot be resolved by a single indicator result. The interruption may involve a power failure, alarm, aborted cycle, equipment fault, door opening, or operator intervention. The central question is whether the intended sterilization process was completed and adequately documented for the specific load.

This article provides an editorial quality-assurance framework. It is not a CDC- or FDA-prescribed protocol for interrupted cycles, and the supplied sources do not establish one universal hold, reprocess, or release algorithm for every sterilization technology or event. Sterilizer-manufacturer instructions, device-manufacturer reprocessing instructions, the facility’s validated procedure, and authorized quality review should control disposition.

CDC describes sterile processing as a linked system involving device preparation, packaging, loading, sterilant quality, cycle selection, monitoring, and documentation. Mechanical, chemical, and biological monitoring provide different types of information and should be interpreted together rather than treated as interchangeable. [1]

First response: place the load on hold

As a facility-control measure, place the affected load on hold while the event is evaluated. This is a prudent operational recommendation, not a universal CDC or FDA requirement. Identify and segregate the items associated with the interrupted cycle, including any items whose identity or association with the load is uncertain. Do not return them to inventory, a procedure area, or a point of use while their status remains unresolved.

Use a visible status such as hold—sterilization status under investigation. If the organization uses electronic tracking, apply an equivalent status that prevents routine release. The purpose is not to declare failure prematurely. It is to prevent an unresolved process from being treated as successfully completed before the available evidence has been reviewed.

If the sterilizer door opened during or after the interruption, record that fact and evaluate it under the approved facility procedure. The supplied sources do not establish one universal disposition for every door-opening event. The effect of the event may depend on the technology, cycle stage, package condition, handling, and the facility’s documented acceptance criteria.

Implantable items may require additional quarantine or release handling under facility policy. CDC recommends, where feasible, withholding implantable items from use until biological-indicator results are available and negative. [1]

Capture the event while details are available

Record the following information as soon as practical:

• sterilizer identification and cycle or load number;
• date and time of the event;
• cycle selected and intended load contents;
• operator identity or initials;
• the alarm, error message, or observed abnormality;
• the stage of the cycle when the interruption occurred;
• whether the chamber door opened or remained closed;
• the mechanical printout, electronic record, or exported cycle data;
• chemical-indicator observations, including internal and external indicators where used;
• biological-indicator information, if one was included; and
• the disposition decision and approving person.

CDC recommendations identify load identification, contents, exposure parameters, operator information, and mechanical, chemical, and biological monitoring results as important elements of sterilization records. [2]

Why one indicator cannot resolve the event

A chemical indicator may show exposure to one or more conditions associated with a sterilization process. A biological indicator provides different evidence, while the mechanical record documents the equipment’s recorded process conditions. These monitoring methods are complementary rather than interchangeable.

FDA’s chemical-indicator guidance is device and regulatory guidance concerning chemical indicators and their use in submissions; it is not, by itself, a healthcare sterile-processing protocol. The guidance describes chemical indicators as devices intended to monitor one or more parameters of a sterilization process and discusses chemical indicators, biological indicators, and mechanical monitors as components of a monitoring program. [3] For healthcare monitoring practice, CDC states that chemical indicators do not prove sterilization. [1]

Accordingly, a favorable chemical-indicator result should not be used by itself to establish that an interrupted cycle completed the intended process. It should be considered with the mechanical record, biological-indicator information when applicable, load details, packaging condition, and the facility’s approved procedure.

A biological-indicator result also requires context. A negative result may provide relevant evidence, but its significance depends on the sterilization technology, the complete cycle record, the load, and the facility’s approved procedure. The supplied sources do not establish that a negative biological indicator universally resolves an aborted or otherwise uncertain cycle. Teams should therefore follow the applicable technology-specific procedure and document how all available evidence was weighed, particularly when the mechanical record is incomplete, an alarm remains unexplained, packaging is compromised, or load identity is uncertain.

Review the cycle record and the physical load

Begin with the process record. Compare the actual cycle data with the intended cycle and the facility’s documented acceptance criteria. Review whether the record shows:

• the correct cycle selection;
• completion of the required phases;
• the expected exposure conditions;
• any excursion, alarm, or aborted phase;
• adequate data continuity; and
• a clear end-of-cycle status.

Do not fill gaps in the record with assumptions. If the sterilizer display, printout, or electronic system does not establish what occurred, document the uncertainty rather than reconstructing an acceptable cycle from memory. The facility procedure should identify how such uncertainty is reviewed and who is authorized to make the disposition decision.

Next, inspect the load and packaging. Look for wet packs, damaged wraps or pouches, compromised container filters or closures, displaced labels, opened packages, and signs that the load was handled during or after the interruption. Packaging integrity is part of the overall sterilization system. FDA inspection guidance identifies packaging-integrity verification as relevant to sterilization process control, but that guidance applies to regulated manufacturing environments and is used here only as an analogous quality-system reference—not as direct healthcare release authority. [4]

Separate three different questions

1. Was the sterilization cycle completed?

Answer this primarily from the cycle record and the equipment’s status. An aborted or incomplete cycle should not be documented as completed merely because the load was exposed for part of the intended program.

2. Was the process acceptable for the intended load?

Compare the documented process with the validated or approved process, load configuration, packaging system, and facility procedure. A technically completed cycle may still require review if the wrong cycle, load arrangement, or packaging configuration was used.

3. Was sterility maintained afterward?

Even when the process record is acceptable, evaluate whether packaging was opened, damaged, wet, contaminated, or otherwise compromised during handling.

Keeping these questions separate prevents a common error: treating a completed machine cycle as equivalent to a released sterile product.

Disposition: follow the approved procedure

There is no universal disposition for every interrupted cycle based only on the fact that the record is incomplete. Hold, reprocessing, additional review, or release may be considered only within the facility’s authorized, technology-specific procedure and quality system. The review should account for the sterilization technology, cycle stage, equipment record, load and packaging, monitoring results, item identity, and any door opening or subsequent handling.

Release must not be interpreted as permission to release an incomplete or aborted cycle simply because an indicator appears favorable. Release requires documented, technology-specific acceptance criteria, evidence that the intended process was completed or otherwise meets the facility’s validated requirements, traceability to the specific load, and authorization by the person or function designated in the facility procedure.

Reprocessing may be required when the approved procedure determines that the cycle was incomplete, acceptance criteria were not met, a critical alarm remains unresolved, the available record cannot establish acceptability, or packaging integrity is compromised. This is not an automatic universal rule; the decision must follow the applicable procedure and the requirements for the technology, load, packaging system, and device.

Before reprocessing, follow the device manufacturer’s instructions and confirm that instruments can safely undergo another processing cycle. If an item is damaged or its processing history is uncertain, route it through the applicable technical, quality, or device-management process rather than automatically returning it to service.

When documented review may support release

A documented review may support release only when the organization’s approved procedure defines objective acceptance criteria and the available evidence demonstrates that the intended process was completed and remains acceptable for the specific load. Depending on the technology, the review may include a complete and acceptable cycle record, correct load configuration, satisfactory monitoring results, intact packaging, and traceability linking the items to the cycle.

Any parametric-release approach should be used only when authorized by the organization’s quality system and applicable requirements. CDC describes the importance of understanding and directly monitoring physical conditions where such approaches are used; the supplied source does not establish a universal interrupted-cycle release pathway. [1]

Close the loop: corrective action and traceability

After disposition, investigate the cause and determine whether additional loads may be affected. Consider utility interruption or voltage instability; sterilizer maintenance, calibration, or sensor issues; incorrect cycle selection or loading; software, printer, or data-transfer failure; door, gasket, valve, or leak-related problems; operator training or procedure clarity; and similar alarms or incomplete records from earlier loads.

Document affected load numbers, item disposition, notification or recall assessment when applicable, corrective action, and verification of return to service. Trend repeated interruptions by sterilizer, shift, cycle, alarm type, and contributing condition. A single event may be isolated; a pattern may indicate a broader system problem.

Practical checklist

1. As a facility-control measure, place the affected load and any uncertain items on hold.
2. Preserve mechanical and electronic records.
3. Record the interruption, alarm, cycle stage, and door status.
4. Verify load identity and contents.
5. Review the complete cycle record against documented, technology-specific criteria.
6. Inspect packaging and indicators.
7. Interpret biological-indicator results within the applicable procedure and the full event record.
8. Determine whether the facility’s authorized procedure supports continued hold, reprocessing, additional review, or release.
9. Do not release an incomplete or aborted cycle without documented acceptance criteria, evidence supporting acceptability, traceability, and authorized approval.
10. Document the decision and authorization.
11. Assess whether other loads or released items are affected.
12. Trend the event and complete corrective action.

Limitations and educational disclaimer

This article provides a general editorial quality-assurance framework, not a CDC- or FDA-prescribed interrupted-cycle protocol. It does not replace the sterilizer manufacturer’s instructions, medical-device manufacturers’ reprocessing instructions, facility policy, applicable regulations, or a validated release procedure. The appropriate disposition may differ by sterilization technology, load type, packaging system, implantable-item policy, and event circumstances. This content is educational and is not patient-specific medical advice.

References

1. Sterilizing Practices. Centers for Disease Control and Prevention. 2024-02-27.
2. Recommendations for Disinfection and Sterilization in Healthcare Facilities. Centers for Disease Control and Prevention. 2024-02-27.
3. Premarket Notification [510(k)] Submissions for Chemical Indicators. U.S. Food and Drug Administration. 2002-08-14.
4. Sterilization Process Controls. U.S. Food and Drug Administration. 2022-03-29.

Educational overview. Follow the applicable product instructions, validated procedures, local regulations and your facility’s approved policies.