(118 days)
The NAMSA Biological Indicator Spore Strip (single species Geobacillus stearothermophilus ATCC® 7953, product code STS-05R, or dual species Geobacillus stearothermophilus ATCC® 7953 and Bacillus atrophaeus ATCC® 9372. product code STNS-65R) is intended for use in testing the efficacy of chemiclave sterilization.
Performance characteristics are established for exposure at 132ºC for 20 minutes in a MDT Harvey Chemiclave model EC5500 chemiclave sterilizer. Vapo-Steril Solution is the sterilant utilized in the MDT Harvey Chemiclave sterilizer. The solution was cleared under 510(k) number K984270. The validation load used for evaluation of the device performance characteristics consisted of stainless steel dental instruments in a wrapped tray with a mass of 1 kg.
A reduced incubation time of 72 hours for chemiclave sterilization at 132°C has been validated when the Biological Indicator Spore Strips are used in conjunction with Tryptic Soy Broth (TSB) modified with Bromocresol Purple and incubated at 58° - 62°C.
The Biological Indicator Spore Strips are typically used in a dental office but may be used by other small healthcare offices which utilize chemiclave processes to sterilize instruments. The spore strips are utilized to verify the chemiclave exposures were effective at killing the Geobacillus stearothermophilus bacterial spores present on the strips in high volume.
Modification to K113221 are to include chemiclave sterilization at 132°C for 20 minutes in a Harvey model EC5500. The predicate device was not specific to sterilizer type or model number but rather is legally marketed for use in monitoring the chemiclave process. Specificity of the chemiclave model in no way affects the safety or effectiveness of the device.
NAMSA Biological Indicator Spore Strips are easy to use; simply place the spore strips in the most difficult area to sterilize and process the load as normal. After exposure, remove the spore strips and aseptically transfer to growth medium and incubated. After incubation if no signs of bacterial growth are present, the sterilization cycle was effect.
The spore strips may be aseptically transferred to standard media such as Tryptic Soy Broth (TSB) and incubated for a minimum of 7 days. Growth will be indicated by the presence of turbidity. Conversely, the strips may be cultured using TSB which has been modified with a pH indicator (Bromocresol Purple) for a reduced incubation time of 72 hours. Growth will be indicated by a change in color of the media from purple to yellow and/or presence of turbidity.
Biological Indicator Spore Strips consist of a 1.25" x 0.25" filter paper strip which has been inoculated with either single species (Geobacillus stearothermophilus ATCC® 7953 at a population level of 105 per strip), or dual species (Geobacillus stearothermophilus ATCC® 7953 at a population level of 105 and Bacillus atrophaeus ATCC® 9372 at a population level of 106 per strip). The spore strips are individually packaged in a 30# glassine pouch.
This document describes the NAMSA Biological Indicator Spore Strip, a device intended to test the efficacy of chemiclave sterilization. However, the provided text does not contain a typical acceptance criteria table with reported device performance metrics in the format usually associated with AI/ML device studies. Instead, it outlines the technological characteristics of the device and a list of testing performed to demonstrate substantial equivalence to a predicate device.
Given the nature of this submission (a 510(k) for a biological indicator, not an AI/ML device), the "acceptance criteria" discussed are primarily about meeting performance characteristics analogous to existing predicate devices, rather than predefined statistical thresholds for a new analytical algorithm.
Here's an attempt to extract the relevant information based on the provided text, reformatted to fit the request where possible, keeping in mind the device is a biological indicator, not an AI algorithm.
1. Table of Acceptance Criteria (Technological Characteristics) and Reported Device Performance
The acceptance criteria are implicitly defined by the properties of the predicate device and the new device's ability to demonstrate substantial equivalence in key performance characteristics. The document presents a comparison of the new device's technological characteristics against the predicate device.
| Characteristic | Acceptance Criteria (Predicate Device) | Reported Device Performance (NAMSA Spore Strip) |
|---|---|---|
| Product Type | Biological Indicator | Biological Indicator |
| Intended Use | Chemiclave at 132°C | Chemiclave 132°C for 20 minutes, Harvey Model EC5500 |
| Construction | Paper spore strip in glassine | Paper spore strip in glassine |
| Organism | G. stearothermophilus, ATCC® 7953 | G. stearothermophilus, ATCC® 7953 |
| Viable Spore Population | 10^5^/strip | 10^5^/strip (single species) or 10^5^ G. stearothermophilus and 10^6^ B. atrophaeus (dual species) |
| Certified Resistance Characteristics | Dvalue at 132°C: 1.0 to 3.0 Minutes; Survival: 5 min; Kill: 15 min | Dvalue at 132°C: 1.0 to 3.0 Minutes; Survival: 5 min; Kill: 15 min |
| Incubation Temperature | 60°±2°C | 60°±2°C |
| Readout Time in Modified Culture Medium | 72 hours | 72 hours |
| Shelf Life | Minimum of 18 Months | 18 Months |
Study Proving Acceptance Criteria is Met:
The document describes a series of studies designed to demonstrate that the NAMSA Biological Indicator Spore Strip is substantially equivalent to the predicate device and performs as intended. These include:
- Survival-Kill Window Verification: Demonstrated equivalence with the predicate device at the manufacturer's certified chemiclave resistance characteristics (5-minute survival, 15-minute kill). This was also verified at the end of the device's shelf life.
- Population Evaluation: Confirmed equivalent population levels to the predicate device.
- Readout Time Evaluation: Confirmed equivalent reduced incubation times to the predicate device.
- Resistance Characterization (D-value Determination and Verification): Determined D-values at 124°C, 132°C, and 140°C using the Fraction Negative Method. Verified D-values using expired Vapo-Steril solution to account for its full shelf life.
- Load/Chamber Evaluation Studies: Verified device performance in a full chamber with a standard load (stainless steel dental instruments in a wrapped tray with a mass of 1 kg) to confirm no negative influence on sterilization conditions.
- Quantitative Determination of Pre-Exposure Phase Lethality: Quantified spores killed prior to the exposure phase across various load conditions and temperature extremes.
- Carrier and Primary Packaging Material Evaluation: Assessed inhibitory properties and degradative changes of materials.
- Holding Time Assessment: Verified that the Biological Indicators (BIs) were not negatively impacted if left at room temperature for 96 hours post-exposure prior to incubation.
- Recovery Protocols - Reduced Incubation Time (RIT): Determined that the 72-hour RIT claim remains valid even with a 96-hour delay in incubation post-exposure.
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the specific sample sizes (number of biological indicators or test runs) for each individual test or for a single "test set" in the context of an algorithm. However, testing involved:
- Evaluation of "NAMSA's Biological Indicator Spore Strips" for population and readout time.
- "Three lots of the device" were evaluated for D-values with expired Vapo-Steril solution.
- "Standard chemiclave sterilizer" at "standard 132°C cycle for 20 minutes."
- "Validation load...consisted of stainless steel dental instruments in a wrapped tray with a mass of 1 kg."
- "BI's not processed...immediately following exposure are not negatively impacted" if left at room temperature for 96 hours.
The provenance of data is not explicitly stated in terms of country of origin, but all testing appears to be conducted by NAMSA (North American Science Assoc., Inc.) to support their 510(k) submission to the US FDA. The studies are prospective in nature, as they involve performing specific tests on the device under defined conditions.
3. Number of Experts and Qualifications for Ground Truth
This type of submission for a biological indicator does not typically involve human experts establishing "ground truth" for a test set in the way an AI/ML diagnostic device does. The ground truth for biological indicators is established through objective biological and physical measurements:
- Bacterial spore population counts: Measured via standard microbiological techniques.
- Survival/kill determination: Based on the presence or absence of bacterial growth after incubation, which is an objective observation (turbidity or color change).
- D-value calculations: Derived mathematically from experimental data on spore survival at different exposure times.
- Sterilization efficacy: Determined by the physical/chemical process itself and validated by the BI's response.
Therefore, the concept of "number of experts used to establish ground truth" and their "qualifications" is not directly applicable in the same way it would be for medical image interpretation or similar diagnostic tasks. The "experts" in this context would be the microbiologists and engineers who designed and executed the validated test methods.
4. Adjudication Method for the Test Set
Not applicable. As explained above, the "ground truth" for a biological indicator is based on objective biological and physical measurements rather than expert human interpretation requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
Not applicable. This is not an AI/ML diagnostic device that would be used by human readers. Its purpose is to indicate the success of a sterilization process.
6. Standalone (Algorithm Only) Performance Study
Not applicable. This is a physical biological indicator, not an algorithm. Its performance is inherent in its biological and physical properties.
7. Type of Ground Truth Used
The ground truth used is based on:
- Biological viability: Growth or no growth of Geobacillus stearothermophilus spores.
- Quantitative microbiology: Spore population counts and D-value calculations.
- Physical sterilization parameters: Exposure time, temperature, and sterilant concentration, which are controlled experimental variables against which the BI's performance is measured.
8. Sample Size for the Training Set
Not applicable. This is not an AI/ML device that uses training data. The device's performance is based on its inherent physical and biological characteristics, which are then validated through empirical testing, not learned from a dataset.
9. How the Ground Truth for the Training Set was Established
Not applicable, as there is no training set for this type of device.
§ 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).