A dental group's quality lead is asked a simple question at a board meeting: what is our sterilization failure rate? The honest answer takes longer than the question. Failure of what — a load, a cycle, a test strip, a device? Measured against what — every load processed, every biological indicator run, every instrument set released, every patient seen? And reported over what base — a month of tests, a thousand patient visits, a year of sterilizer use?
The question is not pedantic. Canadian and American public health agencies publish infection-control surveillance data that gets quoted in supplier documents as though it described sterilization failures. It usually does not. This article sets out what each source actually counts, which denominator sits underneath each number, and — more usefully — why the resulting figures cannot be divided into one another.
What does each source actually count?
Four bodies of data are routinely cited in Canadian procurement and compliance documents. They were built to answer four different questions.
| Source | What it counts | Denominator | Does it measure reprocessing or sterilization failure? |
|---|---|---|---|
| PHAC — Canadian Nosocomial Infection Surveillance Program (CNISP), via the Health Infobase portal | Healthcare-associated infections and antimicrobial-resistant organisms in participating hospitals: Clostridioides difficile infections, MRSA and VRE bloodstream infections, carbapenemase-producing Enterobacterales infections, and Candida auris infections and colonisations | Rates displayed per 10,000 patient-days, with a toggle to report per 1,000 patient admissions | No. It measures downstream infections, not whether a sterilizer passed or failed |
| CIHI — Hospital Harm measure | Unintended harm occurring during acute inpatient care, grouped into harm categories, and the share judged potentially preventable | Per 100 hospitalisations | No. Reprocessing quality is not one of the harm categories reported |
| CDC — National Healthcare Safety Network (NHSN) | Healthcare-associated infections and device-associated events reported by participating facilities | Patient-days and device-days | No. Sterilization and reprocessing data sit outside the NHSN event definitions |
| Peer-reviewed reprocessing studies | Contamination or biological-indicator failure in reprocessed items | Per item tested (per biological indicator, per endoscope sample) | Yes — these are the sources that measure reprocessing outcomes directly |
The pattern is consistent and worth stating plainly: no national agency in either country publishes a sterilization failure rate. What the agencies publish is outcome surveillance — infections and harm — with denominators built for hospital-level comparison over time. The reprocessing-specific numbers come from quality-assurance laboratories, research groups, and provincial public health units, and they are built on test-level denominators instead.
What the current Canadian and American figures look like
Canada's national infection surveillance is published through PHAC's CNISP programme. The data portal states the current denominators explicitly: rates are displayed in 10,000 patient-days, and the denominator can be switched to rates per 1,000 patient admissions. The most recent detailed case information is published through the Canada Communicable Disease Report as Healthcare-associated infections and antimicrobial resistance in Canadian acute care hospitals, 2019–2023. The surveillance covers the infection types listed above and is collected from CNISP participating hospitals; it is a hospital-acute-care dataset, not a dental, laboratory or long-term care dataset.
CIHI's contribution is the Hospital Harm measure, which CIHI describes as looking at "unintended occurrences of harm in acute care hospitals that could have been potentially prevented by implementing evidence-informed practices." Healthcare Excellence Canada, which partners with CIHI on the project, summarises the current reading as one in 17 hospital stays in 2024–25 involving unintended harm, with the potentially preventable harm rate remaining at 6 per 100 hospitalisations for the fifth consecutive year, after a period stable at about 5.4 per 100 hospitalisations from 2014–15 to 2019–20. The denominator is the hospitalisation.
The CDC's NHSN is the American counterpart, and its denominators are device-days and patient-days. Its methods are published in the NHSN Patient Safety Component manual. Sterilization and high-level disinfection quality are not among its event types; the CDC's guidance on those processes is a separate document, the Guideline for Disinfection and Sterilization in Healthcare Facilities.
Why can't these rates be divided into one another?
Because the denominator is not a unit of the same kind, and in two cases it is not even an event in the same part of the process.
| Number | Denominator | What one unit represents | Why it does not convert |
|---|---|---|---|
| CNISP infection rate | 10,000 patient-days | A day of inpatient care | One patient-day contains many exposures, including many instrument sets, with no consistent ratio to reprocessing events |
| CIHI hospital harm rate | 100 hospitalisations | One inpatient stay | An admission may involve hundreds of sterilized items or none, depending on the procedure |
| NHSN device-associated rate | Device-days or patient-days | A day of device presence | Device-days are defined for indwelling devices, not for reprocessed instrument sets |
| Dental biological-indicator failure rate | Biological indicator tests submitted | One test on one sterilizer | A test is a quality check on a cycle; several tests may map to a single day of use |
| Endoscope contamination rate | Endoscope samples | One sampled channel set from one reprocessed scope | Sampling method, sampling solution and culture protocol vary between studies |
Three consequences follow.
A high infection rate is not evidence of reprocessing failure, and a low one is not evidence of reprocessing success. Infections have multiple pathways; a hospital can have excellent reprocessing and a rising MRSA bloodstream infection rate for reasons unrelated to the sterilizer room.
A test-level rate cannot be scaled up to a population rate. A failure proportion of 0.20 % of biological indicator tests does not become "0.20 % of procedures" or "0.20 % of patients." The denominator is a test, and the conversion requires assumptions about tests per load, loads per day and items per load that the study does not supply.
Peer-reviewed reprocessing rates are not comparable with each other either. This is the finding the literature itself reports. A retrospective analysis of 90,311 endoscope samples collected between 2004 and 2021 in 490 French hospitals opens by noting that the published contamination level of ready-to-use endoscopes "varies from 0.4 % to 49.0 %" and that comparing or interpreting those values "is quite impossible" given the variation in sampling method (flush versus flush-brush-flush, one channel versus all channels), sampling solution, culture protocol and interpretation criteria. That is the same class of problem, one level down: even within a single process, the number depends on how you looked.
What do the reprocessing-specific studies actually report?
Two published datasets are useful for Canadian readers because both measure reprocessing outcomes directly, on a test-level denominator, and both state their methods.
| Study | Setting and period | What was measured | Denominator | Headline figures |
|---|---|---|---|---|
| External biological indicator testing of dental sterilizers, Saskatchewan, published in BMC Oral Health (2024) | 362 dental offices, 2015–2022, one independent quality-assurance laboratory | Biological indicator strips processed in full sterilizer loads and mailed to the laboratory for colorimetric analysis | 198,771 biological indicator tests | Overall failure rate 0.20 %, falling from 0.51 % in 2015 to 0.15 % in 2022; steam sterilizers (98 % of processing) failed at 0.20 %, dry heat at 1.30 % and chemical vapour at 1.40 %; human error accounted for 91.80 % of failures |
| Endoscope reprocessing, 490 French hospitals, published in Endoscopy International Open (2023) | Private and public hospitals, 2004–2021 | Microbial sampling of reprocessed endoscope channels against French guideline thresholds | 90,311 endoscope samples | Mean ratio of endoscopes at the action level 12.6 %, or 19.5 % including the alert level; colonoscope action-level ratio fell from 28.7 % in 2004 to 14.4 % in 2021 |
Read together, these two datasets make the denominator argument concrete. The dental figure of 0.20 % and the endoscope figure of 12.6 % do not contradict each other, and neither is "wrong." One is the share of mailed-in spore tests that failed; the other is the share of sampled scopes that exceeded a microbiological threshold. Different process, different item, different test, different threshold — and, critically, different unit of analysis. Anyone who puts those two numbers in the same column of a comparison table has already made an error the sources cannot fix.
The dental study also carries a finding that matters more than its rate. Human error accounted for 91.80 % of the failures recorded. A failure rate is therefore more usefully read as a signal about process discipline — loading, cycle selection, packaging, record-keeping — than as a verdict on the equipment. Steam sterilizers, which handled 98 % of the processing in that dataset, showed a failure rate six to seven times lower than dry heat and chemical vapour units.
How should a clinic express its own reprocessing performance?
The practical answer is to name the denominator before quoting any percentage, and to pick a denominator a regulator or auditor can reconstruct from records.
For Ontario dental practice, the monitoring obligation itself supplies a natural denominator. Ontario dental practices work to a daily biological indicator interval — one test for each sterilizer on every day it is used. A weekly biological indicator test is not an Ontario requirement; that interval belongs to the CDC and ANSI/AAMI ST79 baseline used in the United States comparison, rather than to the daily interval that Ontario dental practices work to. Quoting the weekly figure as though it were the provincial obligation is one of the more common errors found in compliance files.
With a daily interval in place, the clinic's own reporting unit becomes the number of biological indicator tests run, which is directly proportional to sterilizer-days of use. That produces three numbers a file can defend:
- Tests run in the period, per sterilizer.
- Tests failed, and the retest outcome for each.
- Retest turnaround, in hours or working days, because the interval between a failed test and a confirmed pass is what determines whether any load was released on a positive result.
Two documentation points are worth setting down while the numbers are being collected. First, a failed biological indicator is a process event, not a device verdict: the corrective action, the retest and the release decision all need to be in the same record. Second, plant-level records — cycle printouts, indicator strips, incubation logs — are what an inspector reconstructs the rate from, so the count is only as good as the retention practice behind it. Our sterilization monitoring range covers indicators, incubation and record-keeping consumables for each of those steps, and the sterilization compliance hub collects the related standards notes.
How do you read a failure rate quoted in a supplier document?
Five checks will resolve most claims, and each takes under a minute.
- Ask what the denominator is. Per test, per load, per item, per patient-day or per admission — the unit changes the meaning completely.
- Ask whether the source measures reprocessing at all. If the citation leads to CNISP, CIHI's Hospital Harm measure or NHSN, it measures infections or harm, not sterilization outcomes.
- Ask for the study year and setting. A dental-office biological indicator study and a hospital endoscope study are not interchangeable evidence, and a 2015 figure describes a different period from a 2022 one.
- Ask whether the comparison is within a method. Comparing two laboratories, two sampling protocols or two thresholds produces a difference that belongs to the method, not the product.
- Ask what conclusion the number is being used to support. A process-discipline conclusion can follow from a test-level rate. A clinical-outcome conclusion cannot.
Where a supplier cites a peer-reviewed source, it can and should link it. Both datasets discussed here are openly available: the dental sterilizer biological indicator study (DOI 10.1186/s12903-024-05152-2) and the endoscope reprocessing analysis (DOI 10.1055/a-1991-1391). A related systematic review of gastrointestinal endoscope contamination rates is available here.
Related Reading
- How often should you run a spore test? Sterilizer monitoring schedules explained
- RCDSO vs CPSBC: sterilization monitoring requirements compared
- Bowie-Dick vs biological indicator: what each test catches
- ISO 11140-1 explained: chemical indicator classes for sterilization
- Sterilization and compliance hub
- Sterilization monitoring range for clinics, labs and care homes
- Learning hub — standards, records and procurement
- Five-pack biological indicator trial pack
- 24-hour self-contained biological indicators, 25-pack
- Wholesale and multi-site ordering desk
Sources
- HAI and ARO rates — Canadian Nosocomial Infection Surveillance Program (CNISP), Public Health Agency of Canada, Health Infobase.
- Canadian Nosocomial Infection Surveillance Program overview, Public Health Agency of Canada.
- Healthcare-associated infections and antimicrobial resistance in Canadian hospitals, Canada Communicable Disease Report, 2026.
- Hospital Harm indicator, Canadian Institute for Health Information.
- Hospital Harm Project, Canadian Institute for Health Information.
- Hospital harm is everyone's concern, Healthcare Excellence Canada, summarising the current CIHI Hospital Harm readings.
- National Healthcare Safety Network (NHSN), US Centers for Disease Control and Prevention.
- Guideline for Disinfection and Sterilization in Healthcare Facilities, US Centers for Disease Control and Prevention.
- Exploring sterilizer performance through external biological indicator testing: a retrospective study, BMC Oral Health, 2024 — DOI 10.1186/s12903-024-05152-2.
- Endoscope reprocessing: retrospective analysis of 90,311 samples, Endoscopy International Open, 2023 — DOI 10.1055/a-1991-1391.
- Gastrointestinal endoscope contamination rates, systematic review, 2022.
- Reprocessing, Public Health Ontario.
Each link above was checked on 26 September 2026. Where a source is hosted on a federal or agency domain that is rate-limited from automated clients, the citation has been verified through an alternate route; see the accompanying delivery note.
Frequently Asked Questions
Is there an official sterilization failure rate for Canada?
No. Health Canada, the Public Health Agency of Canada and CIHI do not publish a national sterilization or reprocessing failure rate. PHAC's CNISP programme reports healthcare-associated infection rates per 10,000 patient-days, and CIHI's Hospital Harm measure reports potentially preventable harm per 100 hospitalisations. Both describe patient outcomes. The published figures that measure reprocessing directly come from quality-assurance laboratories and research groups, on a per-test denominator.
Why can't I compare a Canadian infection rate with a US infection rate?
In some cases you can, if both are reported against the same surveillance definitions and the same denominator. What you cannot do is compare an infection rate with a reprocessing failure rate used as a substitute for it. The CNISP and NHSN programmes are designed for infection surveillance with patient-day and device-day denominators; a biological indicator failure proportion is a test-level figure. Different unit, different process stage, different meaning.
What does "0.20 % failure rate" mean in a dental sterilizer study?
It means one in 500 biological indicator tests failed. In the Saskatchewan dataset, that was the overall figure across 198,771 tests submitted by 362 dental offices between 2015 and 2022. The denominator is the test, so the figure describes how often a spore test came back failing — not how often a patient was exposed, and not how often an instrument set was non-sterile. The same study found human error accounted for 91.80 % of the failures.
Why is the endoscope contamination range so wide, from 0.4 % to 49.0 %?
Because the studies measured differently. Sampling method (flush versus flush-brush-flush, one channel versus all channels), sampling solution, culture technique and the threshold used to call a result non-compliant all vary between published work. The authors of the 90,311-sample analysis describe comparison across those studies as "quite impossible" for exactly that reason. It is a caution about method variance, not a statement that reprocessing quality varies forty-fold in practice.
What denominator should a dental clinic use for its own records?
The most defensible unit for a dental practice is the biological indicator test. The Ontario dental requirement is one test per sterilizer on every day the sterilizer is used, so tests-run tracks sterilizer-days closely and can be reconstructed from logs. Report tests run, tests failed, retest outcome and retest turnaround. Avoid percentage claims against patient numbers, which no monitoring record supports.
Does a weekly spore test satisfy the Ontario dental requirement?
No. A weekly biological indicator test is not an Ontario requirement. The weekly interval is the baseline associated with the CDC and ANSI/AAMI ST79 comparison used in the United States, rather than the daily interval Ontario dental practices work to. The distinction matters in an inspection file, where citing the wrong interval reads as a monitoring programme that was designed against the wrong source.
Where does human error fit into these numbers?
In the dental dataset it accounts for the large majority of failures — 91.80 % — which is why a failure percentage is more usefully read as a process indicator than an equipment verdict. Loading density, cycle selection, packaging and documentation appear in the corrective-action side of that data. When a clinic counts failures, the useful pairing is each failure with the cause recorded at retest, not the rate on its own.
Last updated: 26 September 2026. CliniEco Medical is a licensed medical device establishment (MDEL #35334).
0 commentaire