(57 days)
MicroScan® rapID/S plus™ 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 MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels are read on the WalkAway® SI System or equivalent (upgraded WalkAway® 40 or WalkAway® 96 instruments).
This particular submission is for the antimicrobials Ofloxacin, Norfloxacin, Levofloxacin, Lomefloxacin, Sparfloxacin, and Ciprofloxacin on the Synergies plus" Gram-Negative MIC/Combo Panels.
The Gram-Negative organisms which may be used for Ofloxacin (Ofl), Norfloxacin (Nxn), Levofloxacin (Lvx), Lomefloxacin (Lmf), Sparfloxacin (Sfx), and Ciprofloxacin (Cp) susceptibility testing in this panel are listed in the attached table.
MicroScan® rapID/S plus™ 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 MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels are read on the WalkAway® SI System or equivalent (upgraded WalkAway® 40 or WalkAway® 96 instruments).
The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in Mueller-Hinton Broth to concentrations bridging the range of clinical interest and are presented in micro-titer wells in dried form. The rapID/S plus™ panels are inoculated with a standardized suspension of the organism and incubated at 35℃ in the WalkAway® SI System or equivalent for 4.5 - 18 hours. The minimum inhibitory concentration (MIC) for the test organism is determined by the lowest antimicrobial concentration showing inhibition of growth.
Acceptance Criteria and Study for MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels
This document describes the acceptance criteria and study details for the MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels for determining antimicrobial agent susceptibility, specifically for Ofloxacin, Norfloxacin, Levofloxacin, Lomefloxacin, Sparfloxacin, and Ciprofloxacin.
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria are derived from the "Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices", dated March 8, 2000, and are presented below alongside the device's reported performance.
| Antimicrobial Agent | Acceptance Criteria (Essential Agreement) | Reported Device Performance (Essential Agreement) | Acceptance Criteria (Categorical Agreement) | Reported Device Performance (Categorical Agreement) |
|---|---|---|---|---|
| Ciprofloxacin | N/A (implied high agreement) | 98.3% (640/651) | N/A (implied high agreement) | 92.8% (604/651) |
| Levofloxacin | N/A (implied high agreement) | 98.2% (639/651) | N/A (implied high agreement) | 94.3% (614/651) |
| Lomefloxacin | N/A (implied high agreement) | 98.6% (642/651) | N/A (implied high agreement) | 94.9% (618/651) |
| Norfloxacin | N/A (implied high agreement) | 97.4% (634/651) | N/A (implied high agreement) | 93.5% (609/651) |
| Ofloxacin | N/A (implied high agreement) | 98.3% (640/651) | N/A (implied high agreement) | 93.5% (609/651) |
| Sparfloxacin | N/A (implied high agreement) | 98.6% (561/569) | N/A (implied high agreement) | 96.3% (548/569) |
Note on Acceptance Criteria: The provided text explicitly states that the device "demonstrated substantially equivalent performance when compared with an NCCLS frozen Reference Panel, as defined in the FDA DRAFT document 'Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices', dated March 8, 2000." While specific numerical thresholds for "Essential Agreement" and "Categorical Agreement" for acceptance are not explicitly listed in the provided summary, the reported percentages are presented as successful outcomes in meeting these criteria. The phrase "acceptable performance" is used, implying the reported values met the established thresholds.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Sizes:
- Ciprofloxacin, Levofloxacin, Lomefloxacin, Norfloxacin, Ofloxacin: 651 isolates each.
- Sparfloxacin: 569 isolates.
- Data Provenance: The external evaluation was conducted with a mix of:
- "fresh and stock Efficacy isolates": These likely represent clinical isolates.
- "stock Challenge strains": These are likely well-characterized strains used for quality control and validation.
The country of origin is not explicitly stated, but the evaluation compared performance against an "NCCLS frozen Reference Panel," suggesting a standardization against US-based clinical microbiology guidelines. The study appears to be prospective in nature for the efficacy isolates and challenge strains as they were evaluated against a reference method.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The submission does not specify the number or qualifications of experts used to establish the ground truth. The ground truth was established by an NCCLS frozen Reference Panel. This implies a standardized laboratory method, likely performed by trained laboratory professionals, rather than a subjective expert consensus scenario often seen in image-based diagnostics.
4. Adjudication Method for the Test Set
The adjudication method is not explicitly described. However, the study involved comparing the device's results to an "NCCLS frozen Reference panel." This typically means that any discrepancies between the device and the reference method would be analyzed, but a formal "adjudication" process with multiple human readers resolving disagreements is not applicable in this context. The reference panel itself serves as the "gold standard."
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This type of study is primarily relevant for diagnostic imaging devices where human reader performance is a key metric. This submission concerns an in vitro diagnostic device for antimicrobial susceptibility testing, where the focus is on the agreement with a reference laboratory method rather than human interpretation of complex images.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, a standalone performance study was done. The study evaluated the performance of the MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels when read on the WalkAway® SI System or equivalent. This automated reading by the instrument constitutes the "standalone" or "algorithm only" performance, comparing its output directly to the reference standard.
7. The Type of Ground Truth Used
The type of ground truth used was comparison to an NCCLS frozen Reference Panel. This method effectively serves as the "gold standard" for determining Minimum Inhibitory Concentrations (MICs) in antimicrobial susceptibility testing, representing a highly standardized and accepted laboratory procedure.
8. The Sample Size for the Training Set
The submission does not explicitly state the sample size used for the training set. The descriptions focus on the external evaluation (test set) and reproducibility/quality control testing. As an in vitro diagnostic device, the "training set" might refer to internal development and validation data, which is not detailed in this 510(k) summary.
9. How the Ground Truth for the Training Set Was Established
Similar to the training set sample size, the document does not explicitly describe how the ground truth for a potential training set was established. However, given the nature of the device (MIC panels), it is highly probable that any internal development or training would also rely on comparisons to established reference methods, such as those defined by NCCLS guidelines, or characterized microbiological strains with known susceptibility profiles.
§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.
(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”