(35 days)
To determine bacterial antimicrobial agent susceptibility. The MicroScan® MICroSTREP plus™ Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci, including Streptococcus pneumoniae. After inoculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually according to the Package Insert. This particular submission is for the addition of the antimicrobial Ampicillin at concentrations of 0.03 to 16 mcg/ml to the test panel. The organisms which may be used for Ampicillin susceptibility testing in this panel are: Streptococcus spp. other than Streptococcus pneumoniae.
The MicroScan® MICroSTREP plus™ Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic streptococci, including Streptococcus pneumoniae. After inoculation, panels are incubated for 20 - 24 hours at 35°C +/- 1°C in a non-CO2 incubator, and read visually according to the Package Insert. The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test. Various antimicrobial agents are diluted in water, buffer or minute concentrations of broth to concentrations bridging the range of clinical interest. Panels are rehydrated with 115 ul Mueller-Hinton broth supplemented with 2-5% lysed horse blood (LHB) and buffered with 50 mM HEPES, after inoculation of the broth with a standardized suspension of the organism in saline. After incubation in a non-CO2 incubator for 20-24 hours, the minimum inhibitory concentration (MIC) for the test organism is manually read by observing the lowest antimicrobial concentration showing inhibition of growth.
Here's a breakdown of the acceptance criteria and study information for the MicroScan® MICroSTREP plus™ Panel with Ampicillin, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Overall Essential Agreement for Ampicillin (compared to NCCLS frozen Reference panel) | 93.4% |
| Reproducibility and Precision for Ampicillin | Acceptable |
| Quality Control Testing for Ampicillin | Acceptable |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: The document mentions "fresh and stock Efficacy isolates and stock Challenge strains" were used for the external evaluation. However, the exact sample size (number of isolates/strains) for the test set is not explicitly stated in the provided text.
- Data Provenance: The data was generated through an "external evaluation," implying independent testing. The text does not specify the country of origin of the data, but the context implies it was likely conducted in the US given the FDA submission. The study involved both "fresh" isolates (suggesting prospective collection at that time) and "stock" isolates/strains (suggesting retrospective use of stored samples).
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Experts:
- The document states the proposed device's performance was compared with an "NCCLS frozen Reference Panel." This implies that the ground truth was established by the NCCLS Reference Panel, which is a standardized method for antimicrobial susceptibility testing. The development and validation of such reference panels typically involve multiple experts and rigorous standardization, but the number and specific qualifications of experts involved in establishing the ground truth for this particular study's reference panel are not detailed in the provided text.
4. Adjudication Method for the Test Set:
- The text describes a direct comparison of the MicroScan® MICroSTREP plus™ Panel with the NCCLS frozen Reference Panel. The "Essential Agreement" metric suggests a comparison of MIC values obtained by both methods. There is no mention of an overt adjudication method (like 2+1 or 3+1) involving human expert review for resolving discrepancies between the test device and the reference standard; the NCCLS reference method is treated as the established ground truth.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done:
- No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not conducted as described in the provided text. The study focuses on comparing the new device's performance to a reference standard, not on the improvement of human readers with or without AI assistance. The device is a diagnostic panel, not an AI assistance tool for human interpretation.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, a standalone performance evaluation was done. The MicroScan® MICroSTREP plus™ Panel itself is the device under test, and its performance is evaluated independently against a reference standard. While human visual reading is part of its intended use ("read visually according to the Package Insert"), the "Essential Agreement" comparison primarily assesses the panel's ability to produce consistent MIC results in comparison to the reference, representing its standalone analytical performance.
7. The Type of Ground Truth Used:
- The type of ground truth used was an expert-established and standardized reference method: the "NCCLS frozen Reference Panel." NCCLS (National Committee for Clinical Laboratory Standards, now Clinical and Laboratory Standards Institute - CLSI) reference methods are considered the gold standard for antimicrobial susceptibility testing.
8. The Sample Size for the Training Set:
- The document does not specify a separate "training set" or its sample size. The information provided is about the performance validation study (test set) of the final device. For a diagnostic panel like this, the "training" (development and optimization) would involve internal R&D processes of the manufacturer, and the details are not typically included in a 510(k) summary focused on validation.
9. How the Ground Truth for the Training Set Was Established:
- As a training set is not explicitly mentioned or detailed in the provided text, the method for establishing its ground truth is unknown from this document.
§ 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).