(1483 days)
EZTest® - Gas self contained biological indicators are for monitoring the efficacy of ethylene oxide gas sterilization processors. Performance characteristics are established in accordance with USP XXIII for the 600mg/l process.
The biological indicator consists of a self-contained unit which includes: bacterial spores inoculated onto a paper carrier, a small glass ampule containing sterile culture medium and color indicator, and a plastic vial that serves as the culture tube. This unit complies to the performance characteristics described in the USP XXIII.
The acceptance criteria and the study proving the device meets them are described below:
1. Table of Acceptance Criteria and Reported Device Performance
The EZTest® - Gas biological indicator is designed to meet the performance characteristics described in the USP XXIII. The document outlines several characteristics that were evaluated.
| Acceptance Criteria (Based on USP XXIII guidelines) | Reported Device Performance |
|---|---|
| Bacterial Spore Species: Bacillus subtilis, ATCC 9372 or equivalent | Bacillus subtilis, ATCC 9372 or equivalent (no specific performance metric, but states that this is the organism used and USP XXIII requires its use for EO sterilization monitoring). |
| Bacterial Spore Concentration: Between 0.5 x 10⁶ and 5 x 10⁶ CFU for a 10⁶ labeled concentration. | Population of spores on paper carrier will be between 0.5 x 10⁶ and 5 x 10⁶, labeled as a 10⁶ concentration. SGM Biotech, Inc. specification matches this guideline. (Performance is stated as meeting the spec, not a measured value from this specific study, but inherent to product design). |
| Sample Purity: (Implied clean culture of target spore species) | No specific performance metric given, but "Sample purity" was an evaluated characteristic. |
| Resistance Characteristics: | |
| - D-values at 600 mg/l EO, 54°C, 60% RH. | "D values at 600 mg/l EO, 54°C, 60% RH" were evaluated. No specific numerical D-value is reported in this summary, but the device is concluded to "meet the USP XXIII requirements" for this parameter. |
| - Survival/Kill times at 600 mg/l EO, 54°C, 60% RH. | "Survival/Kill times at 600 mg/l EO, 54°C, 60% RH" were evaluated. No specific numerical times are reported in this summary, but the device is concluded to "meet the USP XXIII requirements" for this parameter. |
| Incubation Readout Time Validation: 48 hours incubation based on CDRH guideline. | "Validation of 48 hours incubation read out time following the CDRH guideline" was performed. |
| Effect of Holding Time: | "Resistance characteristics were evaluated to determine the effect of holding time after the exposure to the sterilant until incubation, upon the recovery of injured spores." (No specific result provided, but the evaluation was performed). |
| Effect of pH Indicator: | "Evaluation of the effect of the pH indicator upon the recovery of injured spores" was performed. (No specific result provided, but the evaluation was performed). |
| Effect of Sterilization Process on Media Growth Support: | "Validation of the effect of the sterilization process on the ability of the media to support the growth of injured spores" was performed. (No specific result provided, but the evaluation was performed). |
| Product Stability: Stability over 18-month shelf life claim. | "Stability of the product over the eighteen (18) month shelf life claim" was evaluated. (No specific result provided, but the evaluation was performed). |
The ultimate reported performance is that the EZTest® - Gas "meets the USP XXIII requirements" for the tested parameters.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document states that claims were evaluated using "at least three (3) spore lots using different spore crops and different media lots." This indicates that multiple units from these lots would have been tested for each characteristic. However, the exact number of individual biological indicators tested is not specified.
- Data Provenance: The document does not explicitly state the country of origin for the data or whether the study was retrospective or prospective. Given that it's a 510(k) submission to the FDA, the studies would likely have been conducted prospectively under controlled laboratory conditions, possibly in the USA, to generate the required performance data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
This type of device (biological indicator) does not typically involve human experts establishing a "ground truth" in the way an imaging AI algorithm would. The "ground truth" for a biological indicator is determined by the growth or non-growth of bacterial spores after exposure to a sterilization process and subsequent incubation. This is an objective biological outcome, not a subjective interpretation by human experts.
4. Adjudication Method for the Test Set
Not applicable. As explained above, the "ground truth" is an objective biological outcome (spore growth/no growth), not a subjective assessment requiring adjudication by multiple experts.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This type of study is relevant for diagnostic devices that involve human interpretation (e.g., radiology AI), not for biological indicators that assess the efficacy of sterilization directly through objective biological endpoints.
6. Standalone Performance Study
Yes, a standalone study (algorithm only without human-in-the-loop performance) was done. For a biological indicator, "standalone performance" refers to the device's ability to accurately reflect the presence or absence of viable spores after a sterilization cycle. The listed evaluations (D-values, survival/kill times, incubation readout, etc.) directly assess the device's inherent performance characteristics in a controlled laboratory setting, independent of human interpretation to determine the primary outcome. The reading of the color change is a direct function of the device's biological and chemical components, not a human reader's diagnostic skill.
7. Type of Ground Truth Used
The ground truth used is based on biological outcomes (growth or non-growth of Bacillus subtilis spores) and established industry standards as defined by the USP XXIII (United States Pharmacopoeia). This involves direct observation of microbial growth (manifested by a color change in the medium) after defined exposure to ethylene oxide and subsequent incubation.
8. Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning or AI. For a biological indicator, the development and manufacturing process doesn't typically involve machine learning training data. Instead, the "training" (or rather, development and validation) of such a device relies on extensive laboratory testing and adherence to established microbiological and sterilization science principles.
The description implies that the manufacturing process involves "a manufacturing in-process quality control system to specifications defining exacting parameters for production to assure a consistent product and good manufacturing procedures." This ongoing quality control and specification adherence serve a similar purpose to ensuring a consistent "learned" behavior in an AI model, but through traditional engineering and scientific validation.
9. How the Ground Truth for the Training Set Was Established
Not applicable in the AI/ML sense. For this device, the "ground truth" for establishing its design and specifications (analogous to a training set for AI) would have been established through:
- Established microbiological principles: Understanding the resistance of Bacillus subtilis spores to ethylene oxide.
- USP XXIII guidelines: Adherence to defined performance characteristics for biological indicators.
- Historical data and scientific literature: Leveraging decades of knowledge related to sterilization processes and biological indicator design.
- Internal R&D and testing: SGM Biotech's own experimentation to develop their specific media formulation, spore carrier, and device configuration to meet the USP XXIII standards.
The "ground truth" for manufacturing quality assurance is established by testing each lot against the USP XXIII specifications for spore count, resistance, and purity.
§ 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).