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The MicroScan® Dried Gram-Positive MIC/Combo Panel is used to determine quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid media of rapidly growing aerobic and facultative Gram-Positive cocci. After inoculation, panels are incubated for 16 - 20 hours at 35°C +/- 1°C in a non-CO2 incubator, and read either visually or with MicroScan instrumentation, according to the Package Insert.

This particular submission is for a revised QC range of ≥ 0.5 mcg/ml for S. aureus ATCC #29213 with Ampicillin.

The Gram-Positive organisms which may be used for Ampicillin susceptibility testing in this panel are:

Staphylococcus aureus (beta-lactamase and non-beta-lactamase producing) Staphylococcus epidermidis (beta-lactamase and non-beta-lactamase producing) Staphyloccus saprophyticus (beta-lactamase and non-beta-lactamase producing) Streptococcus faecalis (Enterococcus) Streptococcus pyogenes

The MicroScan® Dried Gram-Positive MIC/Combo Panels with Ampicillin are not intended for use with Streptococcus pneumoniae and viridans streptococci.

MicroScan® Dried Gram-Positive 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 Gram-Positive cocci.

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-CO, 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.

Here's a breakdown of the acceptance criteria and study information for the MicroScan® Dried Gram-Positive MIC/Combo Panel, based on the provided documents:

The 510(k) submission (K020140, later referenced as K020160) is specifically for a revised Quality Control (QC) range for Ampicillin with S. aureus ATCC 29213 on an already marketed device, the MicroScan® Dried Gram-Positive MIC/Combo Panel. Therefore, the information primarily focuses on validating this specific QC range change rather than the entire device's performance.

1. A table of acceptance criteria and the reported device performance

The document states that the proposed MicroScan® Dried Gram-Positive MIC/Combo Panel 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 acceptance criteria for the revised QC range are not explicitly detailed in the provided text, the standard for antimicrobial susceptibility devices typically involves:

• Essential Agreement (EA): Agreement within +/- 1 two-fold dilution between the test device and the reference method.
• Categorical Agreement (CA): Agreement in the interpretive category (Susceptible, Intermediate, Resistant) between the test device and the reference method.
• Discrepancy Rates: Acceptable rates for Very Major Errors (VME), Major Errors (ME), and Minor Errors (mE). VME occurs when a resistant isolate is reported as susceptible. ME occurs when a susceptible isolate is reported as resistant. mE occurs when an intermediate isolate is reported as susceptible or resistant, or vice versa.
• Quality Control (QC) Range Agreement: The QC results must fall within the established acceptable range.

Given this submission is for a revised QC range, the acceptance criteria would primarily revolve around validating the new range for Ampicillin with S. aureus ATCC 29213. This typically means that a high percentage of QC tests performed with the new range must fall within the specified bounds, demonstrating adequate reproducibility and accuracy for internal quality control.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Sample Size for Test Set: The document does not specify the exact sample size for the test set used to validate the revised QC range. It only broadly refers to "data in support of a revised Quality Control range." For AST devices, test sets typically involve a significant number of clinical isolates and challenge organisms. However, for a QC range revision, the sample size would focus on repeated testing of the S. aureus ATCC 29213 strain.
• Data Provenance: Not specified in the provided text. It's likely a controlled laboratory study, but the country of origin or whether it was retrospective/prospective is not mentioned.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

This information is not provided. For antimicrobial susceptibility testing, the "ground truth" (or reference method) is typically established by well-defined reference broth microdilution methods, often performed by trained microbiologists following standardized protocols, not individual "experts" in the same sense as image interpretation. The document mentions comparison to "an NCCLS frozen Reference Panel," which implicitly establishes the reference method.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

This information is not applicable and not provided. Adjudication methods like 2+1 are used for resolving disagreements among human readers in studies, particularly in image interpretation, where subjective decisions are made. For a quantitative test like MIC determination, the NCCLS (now CLSI) reference method provides the objective "ground truth" against which the device is measured.

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

This information is not applicable. The device is a diagnostic an in vitro diagnostic (IVD) device for antimicrobial susceptibility testing, not an AI-assisted diagnostic tool that aids human readers in interpretation. Therefore, an MRMC study comparing human reader performance with and without AI assistance is not relevant here.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

The device is an automated or semi-automated system for determining Minimum Inhibitory Concentrations (MICs). While it can be read visually, the "MicroScan instrumentation" implies an automated reading component. The "substantially equivalent performance" claim would inherently reflect the standalone performance of the device (or its automated reading capabilities if used) compared to the reference standard. The study validates the device's ability to accurately determine MICs, which is its standalone function.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

The ground truth used is an NCCLS frozen Reference Panel. This implies that the reference method is based on the National Committee for Clinical Laboratory Standards (NCCLS, now Clinical and Laboratory Standards Institute - CLSI) standard broth microdilution method, which is the recognized gold standard for antimicrobial susceptibility testing. The frozen reference panels are carefully prepared and verified to ensure accurate MICs.

8. The sample size for the training set

The document does not provide information about a "training set." For this type of IVD device, the development process would involve internal validation and optimization, but the 510(k) summary focuses on the performance of the finalized device (the "test set" in broader terms) against a recognized reference method. It's less about training a machine learning model and more about validating the analytical performance of a chemical/biological assay.

9. How the ground truth for the training set was established

As there's no explicit mention of a "training set" in the context of machine learning, this question is not directly applicable. For the overall development of the MicroScan panels, the "ground truth" for calibrating and developing the various antimicrobial concentrations and interpretive criteria would have been established through extensive studies using standard reference methods (like NCCLS/CLSI broth microdilution) over many years, against a wide range of bacterial isolates.

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