(48 days)
The MicroScan® Dried Gram-Positive MIC/Combo Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-positive cocci. After inoculation, panels are incubated for 16-20 hours at 35℃ +/- 1℃ in a non-CO2 incubator, and read either visually or with MicroScan instrumentation, according to the Package Insert.
This particular submission is for the addition of the antimicrobial Ertapenem at concentrations of 0.002 to 32 mcg/ml to the test panel.
The gram-positive organisms which may be used for Ertapenem susceptibility testing in this panel are:
Staphylococcus aureus (methicillin-susceptible strains) Streptococcus agalactiae
MicroScan® Dried Gram-Positive MIC/Combo Panels are designed for use in determining quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative anaerobic gram-positive cocci.
The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in broth and dehydrated. Various antimicrobial agents are diluted in broth to concentrations bridging the range of clinical interest. Panels are rehydrated with water after inoculation with a standardized suspension of the organism. After incubation in a non-CO2 incubator for 16-20 hours, the minimum inhibitory concentration (MIC) for the test organism is read by determining the lowest antimicrobial concentration showing inhibition of growth.
Here's an analysis of the provided text regarding the acceptance criteria and study for the MicroScan® Dried Gram-Positive MIC/Combo Panels with Ertapenem:
Acceptance Criteria and Study for MicroScan® Dried Gram-Positive MIC/Combo Panels with Ertapenem
1. Table of Acceptance Criteria and Reported Device Performance
The device's performance is assessed against the criteria outlined in the FDA's "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA." The key metric mentioned is "Essential Agreement."
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Essential Agreement | >96% for Ertapenem |
2. Sample Size and Data Provenance
- Test Set Sample Size: The exact number of isolates used in the external evaluation is not explicitly stated. However, it is mentioned that the evaluation was conducted with "fresh and stock Efficacy isolates and stock Challenge strains."
- Data Provenance: The text does not specify the country of origin for the data. The study was an "external evaluation," implying it was conducted independently of the manufacturer, but the location is not provided. The study included both "fresh" and "stock" isolates, indicating a mix of prospective (fresh) and retrospective (stock) data collection.
3. Number and Qualifications of Experts for Ground Truth
The document does not explicitly state the number or qualifications of experts used to establish the ground truth. It refers to an "NCCLS frozen Reference Panel" and "Expected Results determined prior to the evaluation" for challenge strains, implying established reference methods and data rather than real-time expert interpretation for each test case. NCCLS (now CLSI) standards are developed by experts, but the direct involvement of individual experts for this specific study's ground truth establishment is not detailed.
4. Adjudication Method
The adjudication method is not explicitly described. The comparison is made against an "NCCLS frozen Reference Panel" and "Expected Results," which serves as the gold standard. This suggests a direct comparison rather than a human-expert adjudication process for discrepancies.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No Multi-Reader Multi-Case (MRMC) comparative effectiveness study is mentioned. This submission focuses on the performance of the automated system compared to a reference standard, not on how human readers' performance improves with or without the system's assistance.
6. Standalone Performance Study
Yes, a standalone performance study was conducted. The "external evaluation" directly compares the performance of the MicroScan® Dried Gram-Positive MIC/Combo Panels with Ertapenem (the algorithm/device) against an NCCLS frozen Reference Panel. The reported Essential Agreement of >96% reflects the standalone performance of the device.
7. Type of Ground Truth Used
The ground truth used was primarily a reference standard. Specifically, the device's performance was compared to:
- An NCCLS frozen Reference Panel. NCCLS (National Committee for Clinical Laboratory Standards, now Clinical and Laboratory Standards Institute - CLSI) panels are widely accepted reference standards for antimicrobial susceptibility testing.
- Expected Results for stock Challenge strains. These expected results would have been established through validated methods and likely represent a consensus or definitive determination of susceptibility.
8. Sample Size for the Training Set
The document does not provide any information regarding the sample size used for the training set. This is common for submissions of this nature, as the focus is on the validation of the final product with a distinct test set.
9. How Ground Truth for the Training Set Was Established
The document does not provide details on how the ground truth for any potential training set was established. Given the nature of the device (a diagnostic test for antimicrobial susceptibility), if machine learning was involved in its development, the training ground truth would similarly likely rely on established reference methods like NCCLS/CLSI standards or other validated laboratory techniques. However, the text does not elaborate on this aspect.
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).