Veterinary Clinic Case Review: Handling a Positive Spore Test and Recall

A positive spore test sent a small animal veterinary clinic in Ontario into a three-day instrument recall and patient trace. This de-identified case review follows how they ran the recall, found the root cause, and returned to surgery.

What happened when the Thursday load failed?

The clinic ran two compact steam sterilizers and challenged each weekly with a biological indicator (BI) — the widely recommended baseline in veterinary settings. Thursday's routine BI in sterilizer #2 came back positive next day: the 24-hour vial had turned colour, so Geobacillus stearothermophilus survived.

Blaming the test was everyone's first instinct — expired vial, warm incubator, bad batch. The owner chose differently: treat it as real, pull the unit from service, and find out what happened. A repeat indicator came back positive too, removing all doubt.

How did the recall work, instruments first and then patients?

Every load since the last negative result fell under suspicion. The log narrowed it to three days: fourteen wrapped packs covering eleven procedures, from spays to a cruciate repair. Pack numbers matched patient charts, so the recall was precise, not shotgun.

All fourteen packs went into quarantine and the owners of all eleven animals got calls; incision sites were checked and follow-ups offered where warranted. No patient showed signs of infection, and the log confirmed none of the suspect packs reached a sterile field.

That log is the quiet hero of the case. Without it, the window would have stretched from three days to three weeks of guessing from memory. It is a one-page form — inexpensive insurance.

What three problems compounded in the root-cause analysis?

A certified technician went through sterilizer #2 while the team reviewed its own habits. The printout looked normal; the real problems sat elsewhere:

• Missed maintenance. The unit was two months past its scheduled service; the drain strainer was matted with hair and the door gasket had a worn spot.
• Dense, overfilled loads. Towel-wrapped instruments were stacked flat past the validated capacity — and towel packs are among the hardest loads for steam to penetrate.
• Packaging mistakes. Pouches were overstuffed, seals ran close to the instruments, and double-wrapping left air no escape.

Every pack carried a chemical indicator, and every one changed colour — that is the trap. Chemical indicators only prove steam reached the package. Whether the load was sterilized is a question only a biological indicator can answer, via living spores per ISO 11138-3.

What did the corrective plan include?

The owner turned the findings into four commitments, posted beside each sterilizer:

1. Maintenance on a calendar. Service is booked in advance, the drain strainer cleaned daily, the door gasket inspected weekly.
2. Disciplined loading. Capacity limits are printed on each machine; pouches stand on edge and nothing touches the chamber walls.
3. Standardized packaging. Instruments now go into CliniEco Class 4 dual-indicator sterilization pouches sized so contents never crowd the seal; larger sets are wrapped in CliniEco pre-cut sterilization roll sheets cut to length.
4. Faster monitoring. The practice switched to CliniEco 24-hour self-contained biological indicators; weekly testing stays the baseline, and the hospital now runs an extra BI in the first load of every surgery day — a pattern busier services often choose.

How did retesting return the sterilizer to service?

Recovery followed the ANSI/AAMI ST79 script: three consecutive full loads, each challenged with a biological indicator placed bottom front near the drain. All three were negative at 24 hours; only then were the fourteen quarantined packs re-wrapped and reprocessed.

Weekly monitoring continued for a month, and the incident became a training module — new staff study photos of the failed load.

What should other veterinary clinics take from this case?

Three habits carried this practice through a bad week: weekly biological monitoring, a load log for every cycle, and a refusal to explain away a positive result. The failure itself was ordinary — a missed service, a packed chamber, a tired gasket.

For a practice that spore tests weekly and logs every load, a positive BI is a contained, scripted event; for one that does neither, it is a recall with no starting point. So keep the logs honest and indicators in stock.

Related reading

• Rapid Readout Biological Indicator Readers: Every Major Brand Compared (2026 Canada Price Guide)
• BI vs Chemical Indicators: What's the Difference in Sterilization Monitoring?
• The Real Annual Cost of Biological Monitoring: Locked Ecosystems vs Open-System BIs in Canadian Dental Clinics
• free Ontario sterilization compliance log
• printable autoclave sterilization log sheet (free)

Frequently Asked Questions

What should a veterinary clinic do when a spore test comes back positive?

Take that sterilizer out of service and quarantine everything processed since the last negative indicator, then trace packs and patients via the load log. After the fix, run three consecutive full cycles with negative biological indicators per ANSI/AAMI ST79. CliniEco 24-hour self-contained biological indicators keep each confirmation cycle to one day.

How often should veterinary clinics run biological monitoring on their sterilizers?

Weekly biological monitoring is the widely recommended baseline for veterinary settings, mirroring human healthcare practice under ANSI/AAMI ST79; busier services may test more often, as this clinic now does. A 25-pack of CliniEco rapid-readout biological indicators covers about six months of weekly testing on one sterilizer — twelve weeks on two.

Do chemical indicators on sterilization pouches prove that instruments were sterilized?

No. Chemical indicators, including the Class 4 dual indicators printed on CliniEco sterilization pouches, confirm exposure to steam, not spore kill. Only a biological indicator verifies sterilization — which is why ISO 11138-3 sets strict specifications for the Geobacillus stearothermophilus spores used in testing.

Which instruments and patients must be traced after a failed spore test?

Everything processed since the last negative result — surgical packs, dental instruments, implant trays; here, fourteen packs tied to eleven procedures. A numbered load log matches each pack to a patient chart, so the trace takes hours, not guesswork. Keep CliniEco pre-cut sterilization roll sheets in stock for quick re-wrapping.

A positive spore test in a veterinary clinic runs the same recall logic as in a dental office. If a fresh 24-hour readout would help, a free 5-pack of biological indicators is open to clinics, long-term care and labs in Canada, shipping covered.

Related reading: explore our sterilization compliance hub for every industry that sterilizes.

start with our pillar guide on sterility assurance level (SAL) and what 10⁻⁶ really means.

Where to Buy Biological Indicators in Canada

CliniEco Medical supplies these from Ontario with published CAD pricing (MDEL #35334) — no quote required, and each pack ships with the lot number printed on it so your monitoring record stays traceable.

Round Out Your Sterilization Setup

A biological indicator is one link in the chain — these are the pieces it works with:

• Autoclave indicator tape — 3-roll set — the external chemical indicator on every pack
• Class 5 chemical integrators — 100-pack — the in-pack check that pairs with your biological indicator
• Constant-heat pouch sealer — 200 °C, 12 mm seal — for consistent pouch closures

Which format does your sterilizer actually need?

Match the readout time to how fast you need the result: a 24-hour self-contained indicator works in any gravity or pre-vacuum cycle with a standard incubator, while a 3-hour fluorescence tube needs the matching reader. Running one cycle type per day, the 25-pack covers a month; busier clinics move to the 100-pack and cut the per-test cost.

How much do spore tests cost in Canada?

Published pricing runs $2.80 per test on the 25-pack down to $1.89 on the 100-pack — no distributor quote, no account needed.

Not sure which format your sterilizer needs? Generate a free sterilization log sheet first — it maps your cycles and tells you the pack size that fits. Questions about your setup? Ask a Compliance Specialist.