(72 days)
PASCO MIC AND MIC/ID PANELS are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement or 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 Chloramphenicol to Pasco panels at concentrations of 16-0.12 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.
Based on the provided text, here's an analysis of the acceptance criteria and the study that proves the device meets them:
Device: Pasco MIC and MIC/ID Panels (specifically for Chloramphenicol testing)
Intended Use: Quantitatively measuring the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to antimicrobial agents and determining their biochemical identification. This specific 510(k) is for the addition of Chloramphenicol to Pasco panels at concentrations of 16-0.12 mcg/ml for use in determining the susceptibility of S. pneumoniae and non-pneumococcal streptococci.
1. Table of Acceptance Criteria and Reported Device Performance
The study aimed to demonstrate acceptable performance for Essential Agreement (EA) and Category Agreement (CA), and the absence of Major (M), Very Major (VM), or Minor (m) errors. Reproducibility was also assessed.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (S. pneumoniae) | Reported Device Performance (Non-pneumococcal streptococci) |
|---|---|---|---|
| Essential Agreement (EA) | Acceptable (High %) | 100% | 99.3% (initial), 100% (retesting) |
| Major Errors (M) | 0% | 0% (None observed) | 0% (None observed) |
| Very Major Errors (VM) | 0% | 0% (None observed) | 0% (None observed) |
| Minor Errors (m) | 0% (or very low %) | 0% (None observed) | 0% (None observed) |
| Category Agreement (CA) | Acceptable (High %) | 100% | 100% |
| Random Categorical Errors | Low/Acceptable number | 2 (within EA) | 3 minor (within EA) |
| QC Endpoints (S. pneumoniae ATCC 49619) | Within NCCLS acceptable range | Within NCCLS acceptable range | Within NCCLS acceptable range |
| Reproducibility | 100% within +/- 1 dilution | 100% within +/- 1 dilution | 100% within +/- 1 dilution |
Pre-determined Acceptance Criteria (as implied by the "Review Criteria For Assessment Of Antimicrobial Susceptibility Devices (May 1991)"): While specific numerical thresholds for "acceptable" are not explicitly stated in the provided text, the FDA draft document on "Review Criteria For Assessment Of Antimicrobial Susceptibility Devices" (May 1991) would define these, generally expecting high EA and CA (e.g., >90-95%) and very low or zero M/VM errors. The reported performance met these implied criteria.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Sizes:
- S. pneumoniae strains: 101
- Non-pneumococcal streptococci strains: 130
- Reproducibility testing: 12 organisms at each site.
- Data Provenance: The comparative testing was performed at "two sites" using "CDC challenge strains and clinical isolates." This indicates a mix of well-characterized reference strains (CDC challenge strains) and real-world specimens (clinical isolates), suggesting a prospective or at least controlled, designed study. The country of origin is not explicitly stated beyond "CDC challenge strains," which implies a US context.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The text states that a "reference panel" was used for comparative testing. This "reference panel" would serve as the ground truth.
- Number of Experts: Not explicitly stated. The ground truth would typically be established by a reference method, likely performed by trained laboratory personnel following standardized protocols (e.g., broth microdilution or agar dilution as defined by NCCLS/CLSI).
- Qualifications of Experts: Not explicitly stated, but assumed to be qualified microbiologists or laboratory technicians proficient in performing and interpreting reference antimicrobial susceptibility testing methods.
4. Adjudication Method for the Test Set
The text does not describe an adjudication method for the test set. Instead, it compares the device's results directly against a "reference panel." This indicates a direct comparison for agreement percentages rather than an independent expert review and adjudication process.
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, an MRMC study was not done. This device is an automated antimicrobial susceptibility test system, not an AI-assisted diagnostic imaging tool for human readers. Therefore, the concept of "human readers improve with AI vs. without AI assistance" does not apply here.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, a standalone study was performed. The "Pasco test panel" (the device) was directly compared to a "reference panel." The results of the Pasco system, which involves reading of visible growth or color changes as described in the package insert (an automated or semi-automated process for reading results from the panel), were compared to the reference. This is essentially a standalone performance evaluation of the device's ability to determine MICs and categories.
7. The Type of Ground Truth Used
- The ground truth was established by results from a reference panel. This reference panel would typically adhere to a recognized standard method for antimicrobial susceptibility testing (e.g., broth microdilution or agar dilution as per NCCLS/CLSI guidelines), which is considered the gold standard for MIC determination.
8. The Sample Size for the Training Set
- The text does not mention a training set or a sample size for a training set. This is a traditional IVD device, not a machine learning or AI-based device that typically requires a specific training phase. The device's "training" in a broad sense would be its design, manufacturing, and calibration processes based on established microbiological principles.
9. How the Ground Truth for the Training Set Was Established
- As no specific training set is mentioned for an AI/ML context, this question is not applicable. The device's functionality is based on established scientific principles of bacterial growth inhibition and biochemical reactions, not on data-driven learning.
§ 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).