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PASCO MC AND MIC/ID PANELS are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement or category results) the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms.

This 510(k) notification is for the addition of Quinupristin to Pasco panels at concentrations of 8-0.03 mcg/ml for use in determining the susseptibility of Staphylococcus aureus (methicillin-susceptible strains only) and Enterococcus faecium (Vancomycin-resistant and multidrug resistant strains only).

Varying concentrations of antimicrobial agents (usually in two-fold dilutions) are dispensed into the Pasco panels and the panels are then frozen. Panels are thawed prior to use, inoculated with the test organisms, incubated the traditional 16-24 hours and panels are then observed for visible growth or color changes as described in the package insert. The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC). Changes in pH and production of specific metabolites from growth in biochemical substrates are interpreted as described in the package insert for conventional tubed media.

Here's a breakdown of the requested information based on the provided text, focusing on the study conducted for Quinupristin in Pasco MIC and MIC/ID Panels:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document states that performance "supports Substantial Equivalence as outlined in the FDA draft document 'Review Criteria For Assessment Of Antimicrobial Susceptibility Devices' (May 1991)." This FDA document would contain the specific numerical acceptance criteria. Without access to that specific document, the exact numerical thresholds for "acceptable" essential agreement, category agreement, and minor error rates are not explicitly stated in the provided text, but the reported performance achieved "acceptable" status.

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size:
  • Gram-positive strains: 321
  • Gram-negative strains: 334
  • Reproducibility testing: 12 organisms at each of two sites (total could be inferred as 24, but specific count for the 99.5% calculation of "5 organisms with on-scale endpoints" is not definitively stated).
• Data Provenance:
  • Country of Origin: Not explicitly stated, but the submission is to the FDA (United States) and Pasco Laboratories is in Wheat Ridge, Colorado, suggesting US data.
  • Retrospective or Prospective: The test panels were "prepared in-house at Pasco using routine manufacturing procedures" and "Comparative testing... was performed at two sites using CDC challenge strains and clinical isolates." This indicates a prospective study where new test panels were created and tested with specific strains.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Number of Experts: Not explicitly stated.
• Qualifications of Experts: Not explicitly stated.

4. Adjudication Method for the Test Set

• Adjudication Method: Not explicitly described. The comparison was to a "reference panel," implying a comparison to an established method (the "ground truth"). The text doesn't detail how discrepancies between the test panel and reference panel were resolved or adjudicated beyond the listed error types (Major, Very Major, Minor).

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

• MRMC Study: No. This document describes the performance of an Antimicrobial Susceptibility Test device (a laboratory test) against a reference method, not an AI-assisted diagnostic imaging or interpretation system involving human readers. Therefore, an MRMC study with AI assistance is not applicable here.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

• Standalone Performance: Yes, in a sense. The Pasco MIC and MIC/ID Panels are designed to automatically determine the MIC based on visible growth or color changes, and then those results are interpreted. The comparative testing described is essentially a standalone performance evaluation of the device's ability to accurately determine MIC and category results compared to a reference method. It's an algorithm/device-only performance in the context of the assay's output.

7. The Type of Ground Truth Used

• Type of Ground Truth: "Reference panel." This refers to a comparison against an established, validated method for determining antimicrobial susceptibility, implicitly considered the gold standard for this type of testing. "CDC challenge strains" were also used, which are characterized strains with known susceptibilities, further strengthening the ground truth.

8. The Sample Size for the Training Set

• Training Set Sample Size: Not explicitly stated. The document describes the testing of the device for a specific antimicrobial (Quinupristin), not the development or training of the device itself. The Pasco MIC and MIC/ID panels are established devices, and this submission is for the addition of a new antimicrobial. Therefore, it's unlikely a "training set" in the machine learning sense was used for this specific submission. The "routine manufacturing procedures" and "CDC challenge strains" suggest a validation and verification process, not an iterative training process for an algorithm.

9. How the Ground Truth for the Training Set Was Established

• Ground Truth for Training Set: Not applicable, as no training set (in the machine learning sense) is described for this specific submission. The established "reference panel" and "CDC challenge strains" would serve as the basis for validating the performance of newly included antimicrobial agents.

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PASCO MIC AND MIC/ID PANELS are used for quantitatively measuring (with the exception of the Breakpoint/ID panel which provides qualitative measurement or category results) the susceptibility of rapidly growing aerobic and facultative anaerobic bacterial pathogens to a battery of antimicrobial agents and determining the biochemical identification of those organisms.

This 510(k) notification is for the addition of Quinupristin/Dalfopristin to Pasco panels at concentrations of 8-0.03 mcg/ml for use in determining the susceptibility of Streptococcus pyogenes and Streptococcus agalactiae.

Varying concentrations of antimicrobial agents (usually in two-fold dilutions) are dispensed into the Pasco panels and the panels are then frozen. Panels are thawed prior to use, inoculated with the test organisms, incubated the traditional 16-24 hours and panels are then observed for visible growth or color changes as described in the package insert. The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC). Changes in pH and production of specific metabolites from growth in biochemical substrates are interpreted as described in the package insert for conventional tubed media.

Here's a breakdown of the acceptance criteria and study details based on the provided document:

Acceptance Criteria and Reported Device Performance

Note: The document explicitly states that the results "supports Substantial Equivalence as outlined in the FDA draft document 'Review Criteria For Assessment Of Antimicrobial Susceptibility Devices' (May 1991)." This implies the reported device performance met or exceeded the criteria outlined in that FDA document.

Study Details

2. Sample sizes used for the test set and the data provenance:

• Test Set (S. pneumoniae strains): 101 strains
• Test Set (Non-pneumococcal strains): 130 strains
• Data Provenance: The document states "Comparative testing of the Pasco test panel to a reference panel was performed at two sites using CDC challenge strains and clinical isolates." This indicates the data is from multiple sites, includes both CDC challenge strains (likely standardized, external controls) and clinical isolates (real-world patient samples), making it a prospective study in the sense that these specific tests were conducted for this submission. The country of origin is not explicitly stated, but given the FDA submission, it's highly probable to be the United States.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

• The document does not specify the number of experts or their qualifications for establishing the ground truth. It mentions "a reference panel" for comparative testing, implying an established method or standard against which the Pasco panel was compared. This "reference panel" itself would have an established ground truth, likely based on standard microbiological techniques and expert interpretation.

4. Adjudication method for the test set:

• The document does not explicitly state an adjudication method (e.g., 2+1, 3+1). The "reference panel" comparison suggests that the standard method's results served as the reference for determining essential agreement and errors. This implies a direct comparison rather than a separate expert adjudication process for the test results.

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:

• No. This study is for an Antimicrobial Susceptibility Test (AST) panel, not an AI-assisted diagnostic imaging or interpretation device. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable to this device type. The device provides a quantitative or qualitative measurement of susceptibility, not an image or signal for human interpretation.

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

• Yes, in essence. The Pasco MIC and MIC/ID Panels are designed to provide direct measurements of antimicrobial susceptibility. While humans observe visible growth or color changes, the interpretation rules for MIC determination and biochemical identification are predefined in the package insert. The "algorithm" here is the established protocol for interpreting the panel results (e.g., "The lowest concentration of each antimicrobial agent with no apparent visible growth of the test organism is recorded as the minimum inhibitory concentration (MIC)"). The performance metrics (EA, CA, error rates, reproducibility) are based on the panel's ability to produce these results accurately, independent of user-to-user variability in interpretation beyond following the stated protocol.

7. The type of ground truth used:

• The ground truth was established by a reference panel to which the Pasco panel was compared. This reference panel represents expert consensus on standard microbiological methods for determining minimum inhibitory concentrations and biochemical identification. These reference methods are typically well-validated and widely accepted within microbiology.

8. The sample size for the training set:

• The document does not explicitly mention a "training set" in the context of device development. This is typical for AST panels, which are wet laboratory assays rather than machine learning models. The development process involves chemical and biological optimization, not algorithm training on data in the conventional sense. The "training" would be the initial R&D and optimization of the panel's reagents and concentrations.

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

• As there's no explicitly defined "training set" as understood in machine learning, there's no ground truth established in that manner. The development and optimization of the Pasco panels would have relied on established microbiological principles and validated reference methods to achieve accurate and reproducible results for antimicrobial susceptibility testing.

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