(73 days)
To determine antimicrobial agent susceptibility
Microdilution Minimum Inhibitory Concentration (MIC) Panels
Here's an analysis of the provided text regarding the acceptance criteria and study for the MicroScan® Dried Gram-Negative and Gram-Positive MIC/Combo Panels with Cefepime:
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (Gram-Negative) | Reported Device Performance (Gram-Positive) |
|---|---|---|---|
| Overall Essential Agreement (compared to NCCLS Frozen Reference Panel) | Acceptable performance | 98.6% | 95.9% |
| Reproducibility & Precision | Acceptable | Acceptable (regardless of inoculum method or instrument) | Acceptable (regardless of inoculum method or instrument) |
| Quality Control Performance | Acceptable | Acceptable | Acceptable |
Note on Acceptance Criteria: The document states that the device "demonstrated substantially equivalent performance with an NCCLS frozen Cefepime Reference Panel, as defined in the FDA DRAFT document 'Review Criteria for Assessment of Antimicrobial Susceptibility Devices' (dated May 31, 1991)." While the exact numerical thresholds for acceptable performance are not explicitly stated in this summary, the phrasing "acceptable performance" implies that the achieved percentages and findings met the criteria outlined in that FDA draft document. For Essential Agreement in antimicrobial susceptibility devices, thresholds typically refer to agreement within 1-2 dilutions.
Detailed Study Information:
2. Sample size used for the test set and the data provenance
- Sample Size: Not explicitly stated as a numerical value for each panel (Gram-Negative and Gram-Positive). The text mentions "fresh and stock Efficacy isolates and stock Challenge strains" for the external evaluations, but the total number of isolates/strains used is not provided.
- Data Provenance: Not explicitly stated. The studies were "external evaluations," suggesting they were conducted outside of Dade MicroScan's internal labs, but the country of origin or specific institutions are not mentioned. It is implied to be retrospective, as it uses existing "isolates" and "strains."
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not applicable in the conventional sense. For antimicrobial susceptibility testing, the "ground truth" is typically established by a reference method (in this case, the NCCLS frozen Cefepime Reference Panel), not by human expert interpretation of images or other data.
4. Adjudication method for the test set
- Not applicable. The comparison is between the device's output and the reference method's output. There isn't an adjudication process involving multiple human readers as would be seen in interpretive tasks (e.g., radiology).
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
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This type of study is relevant for diagnostic devices where human interpretation is a key component, often assisted by AI. This device directly outputs MIC values, and its performance is compared to a reference method, not to human readers.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, implicitly. The performance of the MicroScan® panels (which are essentially automated or semi-automated systems for determining MICs) was assessed in a standalone manner against a reference method. While human technicians operate the instruments and read results, the "performance" described refers to the device's ability to accurately determine MICs, independent of human interpretive judgment on the MIC value itself. The "Essential Agreement" is purely a comparison of the derived MIC values.
7. The type of ground truth used
- Reference Method: The ground truth was established by the NCCLS frozen Cefepime Reference Panel. This is a well-established and standardized laboratory method for determining antimicrobial susceptibility, considered the gold standard for comparison in these types of studies.
8. The sample size for the training set
- Not explicitly mentioned. The summary focuses on the "external evaluations" which served as the test set for regulatory submission. It does not provide details about any internal development/training sets that might have been used during the product's development phase.
9. How the ground truth for the training set was established
- Not explicitly mentioned. Given the nature of the device, it's highly probable that if a training set were used, its ground truth would also have been established using the NCCLS reference method or a similar gold standard.
§ 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).