(90 days)
To determine antimicrobial agent susceptibility
MicroScan Dried Gram-Negative 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-negative bacilli.
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.
This document describes the premarket notification (510(k)) for Beckman Coulter's MicroScan Dried Gram-Negative MIC/Combo Panels with Levofloxacin (Lvx) for determining antimicrobial agent susceptibility.
Here's an analysis based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Guidance Document: "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", dated August 28, 2009) | Reported Device Performance (Levofloxacin) on the Dried Gram-Negative Panel with Prompt® and WalkAway Instrument |
|---|---|---|
| Essential Agreement (EA) | Not explicitly stated as a numerical threshold in the provided text, but implied as "acceptable performance" compared to a CLSI frozen Reference Panel. | Enterobacteriaceae (except Salmonella spp.): 95.9% |
| Enterobacteriaceae (Salmonella spp.): 100.0% | ||
| Pseudomonas aeruginosa: 93.6% | ||
| Categorical Agreement (CA) | Not explicitly stated as a numerical threshold in the provided text, but implied as "acceptable performance" compared to a CLSI frozen Reference Panel. | Enterobacteriaceae (except Salmonella spp.): 96.7% |
| Enterobacteriaceae (Salmonella spp.): 98.8% | ||
| Pseudomonas aeruginosa: 91.4% | ||
| Reproducibility and Precision | "Acceptable reproducibility and precision" | Demonstrated acceptable reproducibility and precision with levofloxacin (Turbidity or Prompt® inoculum, autoSCAN-4 or WalkAway instrument) |
| Quality Control (QC) Testing | "Acceptable results" | Demonstrated acceptable results for levofloxacin |
Note: The FDA guidance document "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA" typically specifies numerical acceptance criteria for Essential Agreement and Categorical Agreement (e.g., typically ≥ 90% for EA and CA), but these specific numerical thresholds are not explicitly detailed in this provided text. The text only states that the performance was "acceptable" as defined in that guidance document.
2. Sample Size Used for the Test Set and Data Provenance
The document mentions "external evaluations were conducted with fresh, recent and stock Efficacy isolates and stock Challenge strains." However, the exact sample size (number of isolates/strains) for the test set is not provided in the given text.
The data provenance is not explicitly stated in terms of country of origin. It is a retrospective study design since it used "stock Efficacy isolates and stock Challenge strains" and compared the device's performance to a CLSI frozen Reference Panel.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This information is not provided in the document. For antimicrobial susceptibility testing, the "ground truth" is typically established by recognized reference methods, such as the broth microdilution method as outlined by CLSI (Clinical and Laboratory Standards Institute), which inherently does not involve human expert consensus in the same way imaging or clinical diagnosis studies might. The CLSI frozen Reference Panel served as the gold standard for comparison.
4. Adjudication Method for the Test Set
This information is not applicable/provided in the context of antimicrobial susceptibility testing. The comparison is made against a CLSI frozen Reference Panel, which itself is a standardized method, not subject to individual interpretation requiring adjudication.
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
Not applicable. This study is for an antimicrobial susceptibility test system, not an AI-assisted diagnostic tool that involves human readers interpreting cases.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the study describes the standalone performance of the MicroScan Dried Gram-Negative MIC/Combo Panels with Levofloxacin. The performance metrics (EA, CA) are reported for the device ("Dried Gram-Negative Panel inoculated with Prompt® and read on the WalkAway instrument") compared to the CLSI frozen Reference Panel. There is no human interpretation or intervention in the measurement process described beyond the initial setup/inoculation and reading by the automated WalkAway instrument.
7. The Type of Ground Truth Used
The ground truth used was a CLSI frozen Reference Panel. This represents a standardized, reference method for determining antimicrobial susceptibility, widely accepted as the gold standard in microbiology.
8. The Sample Size for the Training Set
Not applicable/provided. The document describes a performance evaluation study comparing a new device to a reference standard; it does not mention a "training set" in the context of machine learning or AI models. This device is not an AI algorithm that learns from data.
9. How the Ground Truth for the Training Set Was Established
Not applicable/provided as there is no training set mentioned for this type of device.
§ 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).