(260 days)
The Anprolene SteriTest consists of a self-contained biological indicator inoculated with viable Bacillus atrophaeus bacterial spores that is placed in a dedicated BI receptacle in the sterilizer. It monitors the efficacy of the 12 hour sterilization cycle at 20-29°C in the Anprolene AN75 Ethylene Oxide Gas Sterilizer. Critical process parameters for the cycle are summarized in Table 1.
The Anprolene® SteriTest consists of a single-use self-contained biological indicator (SCBI) placed in a reusable BI receptacle. It is designed for monitoring the efficacy of the 12 hour sterilization cycle at 20-29°C in an Anprolene AN75 Ethylene Oxide Gas Sterilizer.
The SCBI, the EZTest - Gas Biological Indicator, consists of a plastic vial that serves as the culture tube and a cap including a filter material port to allow ethylene oxide to enter the vial. The plastic vial contains Bacillus atrophaeus spores inoculated onto a paper carrier, and a glass ampoule containing modified soybean casein digest broth and phenol red acting as a pH indicator. There is a chemical indicator printed on the unit label of the SCBI to indicate EO exposure.
Following manufacturer's instructions, the operator inserts the SCBI into the reusable BI receptacle on the purge probe of the Anprolene AN75 Ethylene Oxide Gas Sterilizer, and initiates a 12 hour cycle at 20-29°C. After cycle completion, the SCBI is retrieved and activated by crushing the glass ampoule. The chemical indicator on the SCBI changes from blue to a green/brown color depending on the duration of ethylene oxide exposure. The activated SCBI and an unprocessed control are incubated at 30-35℃ for 48 hours, and monitored for any color change and/or turbidity. Evidence of microbial growth by color change from red-orange to yellow and/or turbidity must be interpreted as a failure to meet the conditions necessary for sterilization (failed cycle); no color change or turbidity indicates conditions for sterilization were achieved (passed cycle).
This document describes the Anprolene SteriTest, AN7508.14, a self-contained biological indicator for monitoring ethylene oxide gas sterilization. The information provided focuses on the performance testing to demonstrate substantial equivalence to a predicate device.
1. Table of Acceptance Criteria and Reported Device Performance
| Test | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Functionality (Resistance Characteristics) | - Partially positive in each half dose cycle when placed in worst-case loads (maximum fabric, metal, and plastic). |
- Negative in each full dose cycle when placed in worst-case loads (maximum fabric, metal, and plastic).
- Rigorous challenge to the Anprolene AN75 sterilization process, meaning its resistance is greater than the same EZTest-Gas Biological Indicator in worst-case locations of maximum loads. | - Partially positive in each half dose cycle.
- Negative in each full dose cycle.
- Resistance characteristics are greater than the same EZTest-Gas Biological Indicator placed in the worst-case locations of the maximum fabric, metal, and plastic loads. |
| Functionality (Suitability for Monitoring) | Device is appropriate for monitoring the efficacy of the sterilization process claimed (12-hour cycle, 20-29°C, 17.6g ± 5% EO, 35-90% RH). | Passed. |
| Shelf Life | Maintains performance specifications (resistance characteristics and correctly indicate pass/fail in cycles) throughout the stated shelf life of 2 years. Stability demonstrates reasonable assurance for effectiveness. | Passed. |
| Viable Spore Population Assay | (Not explicitly stated in the provided text, but implied as per FDA Guidance and ISO 11138-1 requirements) | Met established acceptance criteria. |
| Carrier and Primary Packaging Materials (Growth Inhibition) Evaluation | (Not explicitly stated in the provided text, but implied as per FDA Guidance and ISO 11138-1 requirements) | Met established acceptance criteria. |
| Holding Time Assessment | (Not explicitly stated in the provided text, but implied as per FDA Guidance and ISO 11138-1 requirements) | Met established acceptance criteria. |
| Reduced Incubation Time Validation | (Not explicitly stated in the provided text, but implied as per FDA Guidance and ISO 11138-1 requirements) | Met established acceptance criteria. |
| Equivalence of Resistance Characteristics (with/without vacuum) | Resistance characteristics are equivalent when measured in a Biological Indicator Resistometer in the presence or absence of a vacuum. | Equivalent. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the specific number of biological indicators (sample size) used for each individual test (e.g., functionality, shelf life) in numerical terms for the test set. It mentions "each half dose cycle" and "each full dose cycle" and "each worst-case load," implying multiple tests were conducted under these conditions.
The data provenance is from laboratory bench tests conducted by Andersen Sterilizers, Inc. (the manufacturer). The text does not specify the country of origin of the data beyond implicitly being associated with the manufacturer. The studies are prospective in nature, as they are specifically conducted to validate the device's performance against defined criteria.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
Not applicable. This is a biological indicator for sterilization, and the "ground truth" for its performance is established through microbiological testing (e.g., growth or no growth of spores) and physical measurements against established standards, not through human expert interpretation of images or data in the same way a diagnostic AI might require. The "experts" involved would be microbiologists and sterility assurance professionals conducting and interpreting the tests according to recognized standards.
4. Adjudication Method for the Test Set
Not applicable. Adjudication methods like 2+1 or 3+1 are typically used for establishing ground truth from multiple human readers in diagnostic studies. For biological indicators, the outcome is determined by the objective results of microbiological assays (e.g., color change indicating growth or no growth) and adherence to established physical/chemical parameters for resistance.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not done. This type of study is relevant for diagnostic devices that involve human interpretation (e.g., radiologists reading images) and assessing how AI assistance impacts reader performance. The Anprolene SteriTest is a biological indicator, a device that provides an objective output (color change/turbidity) to monitor a sterilization process, not a diagnostic tool requiring human interpretation with or without AI.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
Yes, the performance evaluation of the Anprolene SteriTest is inherently a "standalone" assessment of the device itself. The biological indicator (which can be considered the 'algorithm' in this context, albeit a physical/biological one) is placed in a sterilizer, and its output (color change upon incubation) directly indicates the success or failure of the sterilization cycle. Human involvement is for placement, retrieval, activation, and interpretation of the objective result, but the indicator's performance is intrinsic to its design and biological response, not a human-in-the-loop diagnostic process.
7. The Type of Ground Truth Used
The ground truth used for performance validation is based on microbiological viability (growth or no growth of Bacillus atrophaeus spores) and physical/chemical parameters of the sterilization cycle.
- Microbiological Ground Truth: This is established by observing whether the Bacillus atrophaeus spores on the indicator survive (indicated by growth and color change) or are killed (no growth, no color change) under defined sterilization conditions (full dose, half dose).
- Performance Standards Ground Truth: The tests adhere to established regulatory and consensus standards such as FDA 2007 "Guidance for Industry and FDA Staff: Biological Indicator (BI) Premarket Notification [510(k)] Submissions" and AAMI/ANSI/ISO 11138-1 "Sterilization of health care products – Biological indicators - Part 1: General requirements." These standards define the expected response characteristics (e.g., specific D-value equivalent, partial kills, full kills).
8. The Sample Size for the Training Set
Not applicable. Biological indicators like the Anprolene SteriTest are not "trained" in the way an AI algorithm learns from a training set. Their performance is inherent to their design, the number of spores, and their resistance characteristics. The tests described are for validation, not training.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no "training set" for this type of device. The device's performance is based on established scientific principles of microbiology and sterilization, and tested against those principles.
§ 880.2800 Sterilization process indicator.
(a)
Biological sterilization process indicator —(1)Identification. A biological sterilization process indicator is a device intended for use by a health care provider to accompany products being sterilized through a sterilization procedure and to monitor adequacy of sterilization. The device consists of a known number of microorganisms, of known resistance to the mode of sterilization, in or on a carrier and enclosed in a protective package. Subsequent growth or failure of the microorganisms to grow under suitable conditions indicates the adequacy of sterilization.(2)
Classification. Class II (performance standards).(b)
Physical/chemical sterilization process indicator —(1)Identification. A physical/chemical sterilization process indicator is a device intended for use by a health care provider to accompany products being sterilized through a sterilization procedure and to monitor one or more parameters of the sterilization process. The adequacy of the sterilization conditions as measured by these parameters is indicated by a visible change in the device.(2)
Classification. Class II (performance standards).