Spore Test Positive: What a Clinic Must Do Before Using the Load Again

A positive spore test means the load it tested cannot be used until the cause is identified and corrected, and any item from that load that already reached a patient has to be traced. The immediate sequence is quarantine, trace, investigate and retest: hold the load, identify every item it contained, work through the likely causes in order, then run three consecutive negative cycles before the sterilizer returns to routine use. The steps below are written so a clinic can act on them during a working day rather than waiting for a service visit.

Have the consumables you need before a failure happens. A 24-hour self-contained biological indicator on the shelf plus a working incubator is what makes the retest possible within the same week; without them, the sterilizer stays out of service while a shipment arrives.

What are the first four steps after a positive result?

Do not skip step 3 to call service. In practice, a control vial that fails to grow, an incubator that drifted, or a process challenge device left on the chamber floor explains a large share of positive results, and none of them requires a technician.

What happens if the load was already used?

Trace it and inform the clinical team. If instruments from the load were used on patients, the infection control lead decides whether a lookback is required based on the procedure, the instrument and the time elapsed. This is a clinical judgement, not a purchasing decision, and it should be documented. The record must show what was identified, who was informed and what was decided.

Do not destroy the load or the packaging. The items, the pouch labels and the indicator vial are the evidence that lets you work out the cause. Keep them in a labelled bin until the investigation closes.

How do you retest a sterilizer after a positive result?

Run three consecutive cycles with an empty chamber, a process challenge device and a biological indicator. All three must be negative. Use the same cycle type that failed, and do not substitute a chemical indicator for the biological test. If any of the three is positive, stop and call service; the unit has a mechanical fault.

Some facilities add a Bowie-Dick test on pre-vacuum units before the three biological cycles, which is sensible because it separates air removal problems from steam and load problems. Record every cycle: date, cycle type, indicator lot, readout time and result. A file with the failing result, the cause, the corrective action and three clean cycles is what an inspector will ask to see.

How long should the sterilizer stay out of service?

Until the three retest cycles are negative and the cause is documented. For a simple cause such as an expired indicator lot, that can be two to three working days. For a mechanical fault, it is until the service report is closed and the retest is complete. Plan for this: a clinic with one sterilizer and no backup will need to borrow capacity or reschedule elective procedures, which is a reason to keep a service agreement and a small stock of spare indicators.

Ontario clinics also need to keep the frequency requirement in view during the event. In Ontario, the RCDSO requires a biological indicator for each sterilizer on every day it is used, so the retest cycles are in addition to that daily requirement, not a substitute for it.

What should be written in the incident record?

Write the timeline, not just the conclusion. Include the date and time the result was read, the load number, the items affected, the checks performed, the cause identified, the corrective action, the three retest results and the date the unit returned to service. Add the names of the people who made each decision. If a patient lookback was considered, record the decision and the reasoning.

Keep the record with the cycle logs rather than in a separate incident folder. When a reviewer opens the log for the month, the failure and the recovery should be visible in sequence, not filed somewhere else.

Related reading

• Biological indicator failures in Canadian dental offices: what reported data shows
• How many biological indicators after a major sterilizer repair?
• What happens if you lose sterilization records to a computer failure?

Download the printable sterilization log, or build one with the log generator so the incident and the retest sit in the same record. Ask a Compliance Specialist at our consultation desk if you are working through a positive result now. Ordering for a clinic, lab or care home? Wholesale and multi-site ordering covers account setup for institutional buyers. Start with a 24-hour biological indicator 25-pack so a retest kit is on the shelf before you need it. Reselling? become a distributor.

Frequently Asked Questions

What do I do first when a spore test is positive?

Stop release and quarantine the load, then trace every item it contained. Check the control vial, indicator storage, incubation temperature and process challenge device placement before calling service.

Can I use the load if the chemical indicator passed?

No. A chemical indicator does not measure lethality. A positive biological indicator means the load cannot be released regardless of the chemical indicator result.

How many negative retests are needed before reuse?

Three consecutive negative cycles with an empty chamber, a process challenge device and a biological indicator. If any retest is positive, stop and call service.

Do I need to notify anyone outside the clinic?

Notify your infection control lead first. A patient lookback decision belongs to the clinical team and should be documented. Report to a regulator only where your provincial framework requires it.

CliniEco Medical is a licensed medical device establishment (MDEL #35334).