When Sterilization Records Disagree: Classifying the Discrepancy Before Disposition

When sterilization records disagree, the first task is not to choose the result that appears most favorable. It is to identify what each result represents, confirm that the evidence belongs to the same load, and follow the facility’s validated procedure for hold, investigation, release, quarantine, recall, reprocessing, or other disposition.

Mechanical records, chemical indicators, biological indicators, and air-removal tests do not answer identical questions. Mechanical monitoring records process conditions such as time, temperature, and pressure. Chemical indicators respond to specified sterilization process variables or combinations of variables. Biological indicators provide a microbiological challenge using resistant microorganisms. These tools support sterilization monitoring, but no individual result, considered alone, establishes that every item in a load is sterile.[1][2]

Start with the facility procedure

A discrepancy should trigger review under the applicable facility procedure. Whether an affected load must be held, whether related loads must be investigated, and whether release, quarantine, recall, reprocessing, or another disposition is required depend on the sterilization modality, the device and load, the monitoring result, and the facility’s validated policy. This article does not establish acceptance criteria or replace those procedures.

Documentation should make the affected load identifiable and the investigation traceable. Record the sterilizer, cycle or load number, date and time, operator, load contents, packaging or configuration information, monitor type, result observed, and the person initiating the review. CDC recommendations call for sterilization monitoring results to be documented for each cycle as applicable.[3]

Classify the disagreement

The following categories help distinguish discrepancies that may look similar but require different review paths.

1. An unacceptable mechanical record

An unacceptable mechanical record may involve an alarm, interruption, aborted phase, unexpected cycle selection, or recorded conditions that do not meet the facility’s documented criteria. Review the complete record rather than relying on a final display or a single apparent pass indication. For steam sterilization, time, temperature, and pressure are among the mechanical observations used in monitoring.[1]

A satisfactory chemical or biological result does not automatically resolve an unacceptable mechanical record. The disposition must follow the applicable procedure, including its requirements for investigation and authorized review.

2. A failed external process indicator

An external process indicator may provide information that an item or package was exposed to a process, depending on the indicator’s design and intended use. A failed or unexpected external indicator should prompt verification of the indicator, its endpoint, placement, exposure, and association with the load. It should not be treated as interchangeable with an internal indicator, a biological indicator, or the mechanical record.

The indicator’s manufacturer instructions and the facility’s procedure should determine how the result is interpreted and what action is required. FDA describes chemical indicators as devices that monitor one or more sterilization parameters through a visible change.[5]

3. A failed internal chemical indicator

An internal chemical indicator is used within a package, tray, container, or test arrangement according to its intended use. An unexpected internal result requires review of the indicator’s intended process, lot and expiration information, storage, placement, exposure, endpoint interpretation, and any applicable control result. Also confirm that the indicator is associated with the correct load and that the package or configuration matched approved instructions.

A failed internal indicator is evidence that the indicator did not reach its specified endpoint under the conditions being assessed. It is not automatically equivalent to a positive biological indicator or an unacceptable mechanical record. The required action depends on the indicator’s intended use and the facility’s acceptance and disposition procedure.[5]

4. A positive biological indicator

A positive biological indicator requires a distinct investigation path. Review the biological indicator identity, incubation conditions and timing, control growth, handling, possible contamination, sterilizer history, load configuration, and any related monitoring results. Follow the organization’s established corrective-action procedure for determining whether affected or related loads require additional action.

CDC notes that positive spore-test results may be associated with operator error, inadequate steam delivery, or equipment malfunction.[1] That observation does not establish the cause of a particular positive result. The cause must be evaluated from the available records and the facility’s procedure.

5. A failed Bowie–Dick or other air-removal test

For a dynamic-air-removal steam sterilizer, a Bowie–Dick test assesses air removal under the applicable test conditions. A failed result should be investigated under the procedure for that sterilizer and may require technical follow-up or taking the sterilizer out of use until the required conditions are met. CDC’s steam-sterilization guidance addresses Bowie–Dick testing in relation to dynamic-air-removal steam sterilizers.[1]

A Bowie–Dick result is not equivalent to a biological-indicator result, and use of a Bowie–Dick test should not be assumed for every sterilizer or sterilization modality. Review the test conditions, cycle, equipment status, and required response separately from other monitoring results.

Resolve the evidence before deciding disposition

Confirm identity and association

Before interpreting a disagreement, verify that the printout, load record, chemical indicator, biological indicator, air-removal test, and any test-pack documentation correspond to the same sterilizer cycle. Check labels, electronic records, handwritten identifiers, transfer information, and incubator records where applicable. An association or labeling error can create an apparent process discrepancy.

Compare the result with the approved load and process

Review whether the load matched the approved configuration and instructions. Consider loading, orientation, stacking, packaging, container condition, product characteristics, hollow or lumen challenges, wetness, damaged packaging, and changes in wrapping or product. CDC identifies packaging, loading, and cycle appropriateness as relevant considerations in sterilization practice.[2]

Also review the monitor’s intended use, placement, exposure, storage, expiration, lot information, endpoint, and controls where applicable. These checks are particularly important when the mechanical record appears acceptable but an indicator result is unexpected.

Determine whether the discrepancy is isolated or recurring

Review recent and adjacent cycles, related monitor results, equipment status, maintenance, repairs, cycle changes, operator practices, and relevant utility or environmental events. A single incorrectly placed indicator presents a different question from repeated unexpected results involving the same sterilizer or process. Trend review may help identify whether the issue is associated with handling, documentation, loading, equipment, or another process element; the facility’s procedure should determine the required scope of review.

Disposition is procedure-specific

Release, quarantine, recall, reprocessing, discard, continued hold, and other dispositions should be selected only as permitted by the facility’s validated procedure and the circumstances of the investigation. The framework in this article does not create a universal hierarchy in which one monitoring method always overrides all others.

For example, an acceptable-looking chemical indicator should not be used to bypass an alarm or unacceptable mechanical record when the procedure requires the load to remain on hold. Conversely, an unexpected indicator result should not be dismissed without confirming its identity, intended use, controls, placement, and relationship to the load. An authorized reviewer should document how the available evidence was compared with the stated acceptance criteria.

If the discrepancy remains unexplained, the record should identify it as unresolved rather than converting uncertainty into an unsupported release decision. A release decision is defensible only when the applicable documented criteria are met and the authorized reviewer records the rationale.

Minimum investigation record

• A description of the disagreement and the affected load.
• The cycle record, load contents, packaging or configuration information, and monitor results.
• Verification of monitor identity, intended use, lot, expiration, storage, placement, endpoint, and controls where applicable.
• Review of alarms, equipment status, maintenance, and relevant recent cycles.
• The acceptance criteria and procedure used for the decision.
• The authorized disposition and its rationale.
• Corrective or preventive actions, including ownership and completion dates, when required by the facility procedure.

Limitations

This educational framework does not replace sterilizer or monitor manufacturer instructions, facility policy, validation documentation, applicable standards or regulations, or qualified technical and infection-prevention review. Requirements differ by sterilization modality, device design, load type, and monitoring result. It is not a sterilizer validation protocol or patient-specific medical advice.

References

1. Steam Sterilization. Centers for Disease Control and Prevention. 2024.
2. Sterilizing Practices. Centers for Disease Control and Prevention. 2024.
3. Recommendations for Disinfection and Sterilization in Healthcare Facilities. Centers for Disease Control and Prevention. 2024.
4. Sterilization Process Controls. U.S. Food and Drug Administration. 2023.
5. Premarket Notification [510(k)] Submissions for Chemical Indicators: Guidance for Industry and FDA Staff. U.S. Food and Drug Administration. 2002.

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