(266 days)
The MicroScan MICroSTREP plus Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of aerobic 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 MicroScan Procedural Manual. Additionally, the panels may be incubated in and read by a MicroScan WalkAway instrument.
This particular Special 510(k) submission is for the addition of updated Streptococcus pneumoniae susceptibility test interpretative criteria for use with tetracycline at concentrations of 0.06 - 16 µg/mL on the MicroSCREP plus Panel (modification to K020939 and K062923).
Tetracycline has been shown to be active in vitro against most strains of microorganisms listed below, as described in the FDA-approved package insert and/or as listed on the FDA Susceptibility Test Interpretative Criteria web site.
Streptococcus spp. Streptococcus pneumoniae
MicroScan MICroSTREP plus Panels are designed for use in determining 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° + 1° in a non-CO2 incubator, and read according to the Procedural Manual.
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 115uL Mueller-Hinton broth supplemented with 2-5% lysed horse blood (LHB) and buffered with 50mM 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. Additionally, the panels may be incubated in and read by a MicroScan WalkAway instrument.
The provided text describes a 510(k) premarket notification for a medical device, specifically the "MicroScan MICroSTREP plus Panels with Tetracycline (0.06-16 ug/mL)". The document details the device's indications for use, its classification, and a summary of the studies conducted to demonstrate its performance.
Here's an analysis to extract the requested information, noting that some details typically found in a comprehensive study report (like the exact number of experts or the specific sample sizes for training sets) are often summarized or omitted in a 510(k) summary.
Device: MicroScan MICroSTREP plus Panels with Tetracycline (0.06-16 ug/mL)
Purpose of 510(k) Submission: Addition of updated Streptococcus pneumoniae susceptibility test interpretative criteria for use with tetracycline.
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria for Antimicrobial Susceptibility Test (AST) systems, as stated in the text, refer to the "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", dated August 28, 2009. While the document doesn't explicitly list a table of acceptance criteria with specific numeric thresholds, it does state that the device demonstrated "substantially equivalent performance" and "acceptable performance" based on Essential Agreement (EA) and Categorical Agreement (CA) when compared to a CLSI frozen Reference Panel.
Based on the provided text, the criteria and performance are:
| Acceptance Criteria (Implicit from Guidance) | Reported Device Performance (vs. CLSI frozen Reference panel) |
|---|---|
| Substantial Equivalence in Performance (as per FDA Guidance) | Streptococcus pneumoniae Essential Agreement (EA) of 90.2% |
| Acceptable Performance (as per FDA Guidance) | Streptococcus pneumoniae Categorical Agreement (CA) of 99.7% |
| Acceptable Reproducibility and Precision | Acceptable reproducibility and precision for tetracycline (demonstrated in K020939 and K062923) |
| Acceptable Quality Control Testing | Acceptable results for tetracycline |
Note on "Acceptance Criteria" for AST devices: Typically, the FDA guidance for AST devices specifies thresholds for Essential Agreement (EA) and Categorical Agreement (CA). For example, EA for a new AST device is often expected to be ≥ 90% and CA is often expected to be ≥ 90% or 95% depending on the specific guidance and organism/drug combination. The reported values of 90.2% EA and 99.7% CA meet commonly accepted thresholds for AST devices.
2. Sample Sizes and Data Provenance
- Test Set Sample Size: The text states "The external evaluations were conducted with fresh and Challenge isolates." It does not provide an exact number or breakdown of these isolates for the test set. It mentions "combined efficacy and challenge data".
- Data Provenance: The document does not specify the country of origin for the data. The study was a comparison against a CLSI frozen Reference Panel, suggesting the data would have been collected in a controlled laboratory setting. It is implied to be prospective in the sense that the "external evaluations" were designed to confirm the acceptability of the updated STIC.
3. Number of Experts and Qualifications for Ground Truth
- The document does not specify the number of experts used to establish the ground truth for the test set.
- The ground truth was established by comparison to a "CLSI frozen Reference Panel." This implies that the reference standard for Minimum Inhibitory Concentration (MIC) determination was used, which adheres to CLSI (Clinical and Laboratory Standards Institute) methodologies. While CLSI methods are expert-developed and standardized, the document does not speak to specific "experts" for this particular study's ground truth assessment.
4. Adjudication Method for the Test Set
- The document does not describe an adjudication method (e.g., 2+1, 3+1). The comparison was made against a "CLSI frozen Reference Panel," which serves as the gold standard, so an adjudication process among human readers comparing findings would typically not be relevant in this type of in vitro diagnostic study.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done in the context of human readers improving with AI vs. without AI assistance. This device is an in vitro diagnostic (IVD) antimicrobial susceptibility test panel. It is designed to provide quantitative or qualitative susceptibility results, which are then interpreted by clinicians. The study design focuses on the accuracy of the device's output (MIC) compared to a reference method, not on human interpretation or the assistance of AI in clinical decision-making. No "AI assistance" component is mentioned for this device.
6. Standalone (Algorithm Only) Performance
- Yes, performance was evaluated in a standalone manner in the sense that the device's measurements (MIC values) were directly compared to the CLSI frozen Reference Panel. The reported EA and CA values reflect the performance of the device itself (including its rehydration, incubation, and reading, either manually or by a MicroScan WalkAway instrument) against a recognized gold standard. The text states: "The Dried MICroSTREP plus Panel inoculated with the turbidity inoculation method and manually read demonstrated acceptable performance...". This means the device's output was assessed independently.
7. Type of Ground Truth Used
- The type of ground truth used was expert consensus / reference method, specifically a CLSI frozen Reference Panel. This panel provides established, standardized Minimum Inhibitory Concentration (MIC) values according to CLSI guidelines, which are developed and validated by experts in antimicrobial susceptibility testing.
8. Sample Size for the Training Set
- The document does not specify a training set sample size. This type of submission (updated STIC for an existing panel) typically involves performance evaluation against a reference method rather than a machine learning training paradigm with separate training and test sets in the conventional sense. The "efficacy and challenge data" mentioned refers to the evaluation of the device performance, not the training of an underlying algorithm.
9. How the Ground Truth for the Training Set Was Established
- As the document does not mention a "training set" in the context of an algorithm or machine learning, the question of how its ground truth was established is not directly applicable to this submission. The ground truth for the performance evaluation (test set equivalent) was established by comparison to a CLSI frozen Reference Panel, which represents a highly standardized and accepted reference method in microbiology.
§ 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).