(88 days)
The VERIFY Spore Test Strip for S40 Sterilant Concentrate is intended to provide users with a means to assess spore kill by S40 Sterilant use dilution in the STERIS automated Liquid Chemical Sterilant Processing Systems (SYSTEM 1E and SYSTEM 1® endo Liquid Chemical Sterilant Processing Systems and enspire 3000 Series Cleaning and Liquid Chemical Sterilant Processing System). A "no growth" result from the VERIFY Spore Test Strip for S40 Sterilant Concentrate after 24 hours of incubation indicates that the liquid chemical sterilization process achieved the conditions necessary to kill at least 1 x 105 viable spores (5 logs) on the spore test strip (STS). It does not confirm the expected full performance of the liquid chemical sterilization cycle.
The Spore Test Strip for S40 Sterilant Concentrate (STS) consists of a 1 % in. x 14 in. filter paper-based strip inoculated with Geobacillus stearothermophilus spores and is enclosed in a glassine envelope. The STS are provided with media vials containing a modified tryptic soy broth with phenol red pH indicator, and a transfer clip. The transfer clip is used to remove the STS from the glassine envelope and serves to hold the strip in a fixed location in either the enspire 3000 Series Cleaning and Liquid Chemical Sterilant Processing System (enspire CLCSPS) or the SYSTEM 1E or SYSTEM 1 endo Liquid Chemical Sterilant Processing system. After the cycle concludes, the transfer clip is used to aseptically transfer the STS from the processor into the growth media for incubation at 55-60℃ for a minimum of 24 hours but may be incubated for up to 7 days. If the media remains red and non-turbid, the user interprets the results as a pass. If the media color turns yellow or is turbid, the user interprets the result as a fail. The shelf life is 12 months when stored at 2-24°C and 30-80% relative humidity (RH) away from sterilizing agents and excessive heat.
The provided text describes a 510(k) premarket notification for a medical device called "VERIFY Spore Test Strip for S40 Sterilant Concentrate." This submission is for a device that already has a predicate (K180553) and the main change is an expansion of its indications for use to include a new processing system, the "enspire 3000 Series Cleaning and Liquid Chemical Sterilant Processing System (CLCSPS)."
The "acceptance criteria" and "study that proves the device meets the acceptance criteria" in this context refer to the performance testing conducted to demonstrate that the expanded use of the spore test strip in the new system is safe and effective, performing as well as the previous approved uses.
Here's a breakdown of the requested information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly defined by the successful outcomes ("PASS") of the performance tests, demonstrating that the device functions appropriately under the new use conditions. The "performance" is the conclusion that the device passed these tests.
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Population Wash Off Stability: Evaluate the population of the spores remaining on the STS after processing without sterilant. | PASS (Demonstrated that the population of spores remaining on the STS after processing without sterilant was acceptable.) |
| Simulated Use: Demonstrate the STS functions appropriately in the enspire CLCSPS. | PASS (Demonstrated that the STS functions appropriately in the enspire CLCSPS.) |
| Bacteriostasis: Ensure no inhibitory effects on the outgrowth of a low number of spores. | PASS (Demonstrated no inhibitory effects on the outgrowth of a low number of spores.) |
2. Sample size used for the test set and the data provenance
The document does not explicitly state the sample sizes (e.g., number of strips, number of runs) used for each of the performance tests (Population Wash Off Stability, Simulated Use, Bacteriostasis).
- Data Provenance: The study was conducted by STERIS Corporation, an American company (Mentor, Ohio). Given the context of a 510(k) submission to the FDA, the data would have been generated in a controlled environment to meet regulatory standards. The document does not specify whether the data was retrospective or prospective, but performance testing for a 510(k) generally involves prospective testing of the device.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This type of device (spore test strip for sterilant efficacy) does not typically involve human expert interpretation of images or clinical outcomes in the same way an AI diagnostic device would. Ground truth is established through laboratory methods (e.g., microbial growth/no growth, quantitative spore counts). Therefore, the concept of "experts" for ground truth establishment in the human-in-the-loop sense, or their qualifications, is not applicable directly to this device. Competent laboratory personnel would conduct and interpret the tests according to established protocols.
4. Adjudication method for the test set
Adjudication methods (like 2+1, 3+1) are common in clinical studies involving human interpretation or subjective assessments. For a biological indicator like a spore test strip, the results (growth/no growth, quantitative counts) are objective, and adjudication is not typically applied in the same manner. The outcome is determined by the presence or absence of growth and quantitative measurements.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
An MRMC study is not applicable to this device. This is not an AI diagnostic device that assists human readers. It is a biological indicator for sterilization processes.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
The device itself is a standalone biological indicator. It provides a result (growth/no growth) based on a biological process (spore killing by sterilant and subsequent incubation). There is no "algorithm" in the sense of artificial intelligence. The device's performance is its ability to accurately reflect the 5-log kill of spores under specified conditions. The performance tests ("Population Wash Off Stability," "Simulated Use," "Bacteriostasis") directly evaluate this standalone performance.
7. The type of ground truth used
The ground truth for this device is based on biological and chemical efficacy.
- Biological Efficacy: The primary ground truth is the presence or absence of Geobacillus stearothermophilus growth after exposure to the sterilant and incubation, indicating whether a 5-log reduction of spores has occurred. This is a direct measure of microbial inactivation.
- Chemical/Physical Parameters: The ground truth also relates to the specific conditions of the sterilization process (e.g., PAA concentration, temperature, time) as defined for the sterilant and the processing systems.
8. The sample size for the training set
This device does not involve machine learning or AI, and therefore, there is no "training set" in the typical sense for algorithms. The "training" of the product's design would be based on historical data, prior knowledge of sterilant efficacy, and established microbiological methods for biological indicators, rather than a data set used to train a predictive model.
9. How the ground truth for the training set was established
As there is no training set for an AI algorithm, this question is not applicable. The underlying scientific principles for spore test strips and sterilization efficacy are well-established through decades of microbiological and chemical research. The "ground truth" for the development of such a device is rooted in these scientific principles and standard test methods (e.g., those from AAMI, ISO).
§ 880.6887 Spore test strip.
(a)
Identification. The spore test strip consists of a carrier or strip with a known number of spores, at least 5 log10 per strip, of known resistance to a particular liquid chemical sterilant in a liquid chemical sterilant processing system. A “no growth” result from the spore test strip after the specified predetermined incubation period indicates that the liquid chemical sterilization process achieved the conditions necessary to kill the specified minimum number of viable spores on the test strip which is 5 log10 spores/strip; it does not confirm the expected full performance of the liquid chemical sterilant processing cycle because full performance is a 6 log10 spore kill in a full liquid chemical sterilization cycle.(b)
Classification. Class II (special controls). The special controls for this device are:(1)
Spore strip characterization. (i) Population of viable spores on strip shall be a minimum of 5 log10 after physical wash off of spores from the strip by exposure to liquid chemical sterilant in the liquid chemical sterilant processing system, which should be validated over the claimed shelf life.(ii) The resistance characteristics of the viable spores on the strip should be defined and be validated over the claimed shelf life.
(iii) The spore strip description should address the carrier material, how the spores are placed on the carrier, and whether there is any feature that minimizes spore wash off. Bacteriostasis of the spore strip materials should be evaluated.
(iv) Incubation time for viable spores on the strip should be validated under the specified incubation conditions over the claimed shelf life.
(2)
Simulated Use Testing. Simulated use testing should demonstrate performance of spore test strip in liquid chemical sterilant/high level disinfectant under worst case in use conditions over the claimed shelf life.(3)
Labeling. Labeling should specify appropriate instructions, warnings, cautions, limitations, and information relating to viable spore population, resistance characteristics, and interpretation of a “no growth” result.