(188 days)
To determine antimicrobial agent susceptibility
To determine gram-negative and gram-positive bacterial susceptibility against the antimicrobial agent Grepafloxacin.
There are no organisms for which MicroScan® panels are intended for testing, that are included in the 'Indications and Usage' as stated in the FDA approval of Grepafloxacin.
The following secondary organisms included for the testing of MicroScan® panels have in vitro data but the safety and effectiveness in treating clinical infections have not been established: Citrobacter freundii, Citrobacter (diversus) koseri, Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Staphylococcus aureus (methicillin-susceptible), Staphylococcus epidermidis (methicillin-susceptible), Streptococcus agalactiae, Streptococcus pyogenes.
The MicroScan® Dried Gram-Positive MIC/Combo Panels with Grepafloxacin are not intended for use with Streptococcus pneumoniae and viridans streptococci.
Microdilution Minimum Inhibitory Concentration (MIC) Panels
MicroScan® Dried Gram-Negative and Gram-Positive MIC/Combo Panels
Acceptance Criteria and Device Performance Study
The provided document describes the 510(k) submission for the MicroScan® Dried Gram-Negative and Gram-Positive MIC/Combo Panels with Grepafloxacin, intended to determine antimicrobial agent susceptibility. The study aims to demonstrate substantial equivalence to an NCCLS frozen Grepafloxacin Reference Panel.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly defined by the statement that the device demonstrated "acceptable performance" and "substantially equivalent" performance when compared to the predicate device, as per the FDA DRAFT document "Review Criteria for Assessment of Antimicrobial Susceptibility Devices" (dated May 31, 1991). The primary metric for performance appears to be "Essential Agreement" with the reference panel.
| Metric | Acceptance Criteria (Implicit from "acceptable" performance vs. predicate) | Reported Device Performance (Gram-Negative) | Reported Device Performance (Gram-Positive) |
|---|---|---|---|
| Overall Essential Agreement | Not explicitly stated numerically, but implied to be high for "acceptable performance" and "substantially equivalent." | 98.8% | 97.5% |
| Reproducibility & Precision | Acceptable | Acceptable | Acceptable |
| Quality Control | Acceptable | Acceptable | Acceptable |
Note: The document does not provide specific numerical thresholds for "acceptable" Essential Agreement, reproducibility, precision, or quality control. Such thresholds would typically be found in the referenced FDA DRAFT document or the study protocol itself. However, the reported values are presented as meeting these unspecified "acceptable" criteria.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Description: The external evaluations were conducted with "fresh and stock Efficacy isolates and stock Challenge strains."
- Sample Size: The document does not explicitly state the total number of isolates (sample size) used for either the gram-negative or gram-positive evaluations.
- Data Provenance: The country of origin for the data is not specified. The study is described as "external evaluations," which typically implies a prospective design where the new device's performance is compared against a reference standard using various new samples. Given the nature of antimicrobial susceptibility testing, this would be a prospective study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This type of study (antimicrobial susceptibility testing) does not typically involve human experts establishing a "ground truth" through visual assessment or clinical judgment in the same way as, for example, an imaging study.
Instead, the "ground truth" (or reference standard) is established by the NCCLS frozen Grepafloxacin Reference Panels. The performance of this reference panel itself is established through a standardized, controlled laboratory procedure, not through expert consensus in the traditional sense. Therefore, the concept of "number of experts" and "qualifications of experts" for ground truth establishment is not directly applicable here.
4. Adjudication Method for the Test Set
Adjudication methods (e.g., 2+1, 3+1) are typically used in studies where multiple human readers independently assess data and discrepancies need to be resolved. This is not directly applicable to an antimicrobial susceptibility testing study comparing results against a laboratory-defined reference standard (the NCCLS panel). The comparison is numerical and algorithmic, not based on human interpretation that requires 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
An MRMC comparative effectiveness study is not mentioned and would not be relevant for this type of device. This device is a diagnostic testing panel designed to determine antimicrobial susceptibility, not an AI-assisted interpretation tool for human readers.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
Yes, the study primarily reflects the "standalone" performance of the MicroScan® Dried panels. The comparison is directly between the results generated by the MicroScan® panels and the NCCLS frozen reference panels. While a human technician operates the panels, the "performance" being evaluated is the accuracy of the panel's determination of MIC values and susceptibility categories compared to the reference, not the human interpretation of ambiguous signals. The document mentions instrument reproducibility testing with "autoScan-4 and WalkAway®," suggesting automated reading, which further supports the "standalone" nature of the performance assessment.
7. The Type of Ground Truth Used
The ground truth used is a reference standard, specifically the NCCLS frozen Grepafloxacin Reference Panels. This is a laboratory-established standard for determining minimum inhibitory concentrations (MICs) of antimicrobial agents.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of this device. Antimicrobial susceptibility panels like this are typically developed based on established microbiological principles and validated against known reference methods, rather than being "trained" like a machine learning algorithm. The study described focuses on validation (testing set performance).
9. How the Ground Truth for the Training Set was Established
As no "training set" for an algorithm is mentioned in the application, this question is not directly applicable. If one were to consider the broader development of the MicroScan® technology, the "ground truth" for establishing the design and performance characteristics of such panels would be rooted in decades of microbiological research, standardized methods (like those from NCCLS/CLSI), and clinical correlation of MIC values with treatment outcomes, but this is beyond the scope of this specific 510(k) submission.
§ 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).