(74 days)
Pasco MIC and MIC/ID panels are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement of category results) the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms.
This 510(k) notification is for the addition of Meropenem to Pasco panels at concentrations of 2-0.03 mcg/ml for use in determining the susceptibility of S. pneumoniae and non-pneumococcal streptococci.
Varying concentrations of antimicrobial agents (usually in two-fold dilutions) are dispensed into the Pasco panels and the panels are then frozen. Panels are thawed prior to use, inoculated with the test organisms, incubated the traditional 16-24 hours and panels are then observed for visible growth or color changes as described in the package insert. The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC). Changes in pH and production of specific metabolites from growth in biochemical substrates are interpreted as described in the package insert for conventional tubed media.
Here's an analysis of the provided text regarding the acceptance criteria and study for the Pasco MIC and MIC/ID Panels (Meropenem), structured according to your request:
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| S. pneumoniae | ||
| Essential Agreement (EA) | High (e.g., typically >90-95% for AST devices) | Initial Testing: 98.1% |
| Retesting: 98.7% | ||
| Major Errors (M) | Low (e.g., typically 90-95% for AST devices) | 99.4% (with 2 additional random categorical errors within EA) |
| Non-pneumococcal streptococci | ||
| Essential Agreement (EA) | High (e.g., typically >90-95% for AST devices) | 100% |
| Major Errors (M) | Low (e.g., typically 90-95% for AST devices) | 100% (with 1 random categorical error within EA) |
| QC Endpoints (S. pneumoniae ATCC 49619) | Within recommended NCCLS acceptable range | Within recommended NCCLS acceptable range (with one exception within range on next test date) |
| Reproducibility | Plus or minus 1 dilution for 100% of organisms | 100% within acceptable plus or minus 1 dilution (for 7 organisms with on-scale endpoints) |
Note: The document refers to the FDA draft document "Review Criteria For Assessment Of Antimicrobial Susceptibility Devices" (May 1991) for the substantial equivalence. While specific numerical acceptance criteria are not explicitly stated as "acceptance criteria," the reported performance is presented as "acceptable" in comparison to these implied standards.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Organisms:
- S. pneumoniae: 101 strains
- Non-pneumococcal streptococci: 130 strains
- Data Provenance: The study used "CDC challenge strains and clinical isolates." This indicates a mix of well-characterized reference strains and real-world clinical samples, suggesting a prospective or retrospective collection depending on how the clinical isolates were sourced. The study was performed at two sites.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not explicitly state the number of experts or their qualifications. However, it indicates that the comparison was made against a "reference panel" and "NCCLS acceptable range" for QC. This implies that the ground truth was established by a recognized reference method (likely a standard microdilution method) and interpreted by individuals trained in microbiological susceptibility testing, presumably following NCCLS guidelines. The involvement of "CDC challenge strains" further suggests that the 'ground truth' for these strains would have been well-established.
4. Adjudication Method for the Test Set
The document does not explicitly describe an adjudication method. However, for the single major error in S. pneumoniae testing, it states that "retest results were acceptable, this error was not considered resolved since the reference method MIC results did not change." This implies that the reference method's result effectively served as the final arbiter (ground truth) and that retesting or alternative interpretation was not deemed to supersede the initial reference result.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done.
- This study is focused on the performance of an automated device (Pasco MIC and MIC/ID Panels) compared to a reference method, not on human reader performance with or without AI assistance.
6. Standalone (Algorithm Only) Performance Study
- Yes, a standalone performance study was done.
- The entire evaluation described is of the Pasco MIC and MIC/ID Panels' ability to determine antimicrobial susceptibility, functioning as a standalone device, by comparing its results to a reference method. There is no human-in-the-loop component described for the interpretation of the panels in this study.
7. Type of Ground Truth Used
The ground truth used was primarily a reference method (e.g., standard microdilution susceptibility testing) as evidenced by the comparison to a "reference panel" and the statement that "the reference method MIC results did not change" after retesting the major error. Additionally, "CDC challenge strains" would have well-established susceptibility profiles. The QC endpoints were compared against "recommended NCCLS acceptable range," which are established standards for susceptibility testing.
8. Sample Size for the Training Set
The document does not provide information regarding a separate training set or its sample size. This type of device (antimicrobial susceptibility test panel) typically has pre-defined reagent concentrations (Meropenem at 2-0.03 mcg/ml) and an established interpretation algorithm (visible growth or color changes as described in the package insert). The "challenge strains" and "clinical isolates" mentioned are implied to be part of the validation/test set.
9. How the Ground Truth for the Training Set Was Established
Since no specific training set is mentioned in the context of machine learning, this question is not directly applicable. If an algorithm were involved (rather than pre-defined chemical reactions and visual interpretation), the ground truth for training would typically be established through expert interpretation of a reference method on a large dataset, similar to the ground truth described for the test set. However, for this device, the "training" (development) of the product likely involved optimizing the chemical formulation and concentrations to align with established antimicrobial susceptibility testing principles and NCCLS guidelines.
§ 866.1620 Antimicrobial susceptibility test disc.
(a)
Identification. An antimicrobial susceptibility test disc is a device that consists of antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro susceptibility of most clinically important bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is ascertained by directly measuring the magnitude of a zone of bacterial inhibition around the disc on an agar surface. The disc-broth elution technique is associated with an automated rapid susceptibility test system and employs a fluid medium in which susceptibility is ascertained by photometrically measuring changes in bacterial growth resulting when antimicrobial material is eluted from the disc into the fluid medium. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).