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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 Cefdinir to Pasco panels at concentrations of 4-0.03 mcg/ml for use in determining the susceptibility of S. pneumoniae and non-pneumococcal streptococci.

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 the study that proves the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size and Data Provenance

• Test Set Sample Size:
  • 101 S. pneumoniae strains
  • 130 non-pneumococcal streptococci strains
  • 12 organisms for reproducibility testing
• Data Provenance: The document states that "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 use of both retrospective (CDC challenge strains) and prospective (clinical isolates) data. The country of origin is not explicitly stated, but "CDC challenge strains" implies a US context.

3. Number of Experts and Qualifications

• This information is not provided in the document. The document refers to "reference panel" and "QC endpoints," but does not detail the human experts involved in establishing ground truth or their qualifications.

4. Adjudication Method

• The document does not specify an adjudication method.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, an MRMC comparative effectiveness study was not explicitly conducted or reported. The study focused on the performance of the device itself (standalone) compared to a reference method, not on human reader performance with or without AI assistance.

6. Standalone Performance

• Yes, a standalone performance study was done. The entire summary describes the performance of the Pasco MIC and MIC/ID Panels (an algorithm/device) in detecting antimicrobial susceptibility, comparing its results to a "reference panel" and established QC standards.

7. Type of Ground Truth Used

• The ground truth was established through a reference panel and QC endpoints for a specific organism (S. pneumoniae ATCC 49619). For the clinical isolates, it's implied the reference panel provided the ground truth, likely based on established microbiological methods.

8. Sample Size for the Training Set

• The document does not provide information on a training set sample size. This device is an Antimicrobial Susceptibility Test, not a machine learning or AI-driven diagnostic device that typically undergoes a distinct training phase. It's a laboratory assay.

9. How Ground Truth for the Training Set Was Established

• As this is not a typical machine learning AI device, the concept of a "training set" with established ground truth as commonly understood in AI development does not directly apply here. The device itself performs a measurement. The "ground truth" for evaluating the device's accuracy is derived from the reference panel and established NCCLS (National Committee for Clinical Laboratory Standards) acceptable ranges for QC organisms.

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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 of 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 Cefdinir to Pasco panels at concentrations of 0.03 to 8 mcg/ml for use in determining the susceptibility of methicillin susceptible strains of S. aureus. Clinical testing of Streptococci spp. including S. pneumoniae with Cefdinir has not been performed with the Pasco system.

Varying concentrations of antimicrobial agents (usually in twofold 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 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 an analysis of the provided text, outlining the acceptance criteria and study details for the Pasco MIC and MIC/ID Panels with the addition of Cefdinir:

Acceptance Criteria and Device Performance for Pasco MIC and MIC/ID Panels (Cefdinir)

The device in question is the Pasco MIC and MIC/ID Panels, with the specific modification being the addition of Cefdinir for susceptibility testing. The study aimed to demonstrate substantial equivalence for the Cefdinir component.

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state pre-defined "acceptance criteria" as clear numerical targets like "Essential Agreement must be >= 95%." Instead, it reports performance that is then qualified as "acceptable." The FDA's "Review Criteria For Assessment Of Antimicrobial Susceptibility Devices" (May 1991) is referenced as the guideline. Based on the reported results, the implicit acceptance criteria relate to achieving "acceptable Essential Agreement (EA)" and "acceptable Category Agreement (CA)" with minimal major and very major errors. Reproducibility is also assessed.

2. Sample Sizes Used for the Test Set and Data Provenance:

• Gram-Negative Strains: 334 strains
• Gram-Positive Strains: 294 strains
• Reproducibility Testing: 9 organisms at each of the two test sites.
• Data Provenance: The study used "CDC challenge strains and clinical isolates." This indicates a mix of reference strains for quality control/standardization and real-world clinical samples, suggesting a robust evaluation. The origin (country) of the clinical isolates is not specified, but the testing was performed at two sites (also not explicitly named, but one appears to be Pasco itself, and the other is referred to as "CMI"). The study appears to be prospective in nature for the comparative testing, as panels were "prepared in-house at Pasco using routine manufacturing procedures" and then tested.

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

The document does not specify the number or qualifications of experts used to establish the ground truth. It refers to comparing the Pasco test panel to a "reference panel" and uses "CDC challenge strains." This strongly implies that the ground truth was established by a reference method (e.g., broth microdilution or agar dilution as per CLSI/NCCLS standards for antimicrobial susceptibility testing) and potentially confirmed by expert microbiologists, but the details are absent.

4. Adjudication Method for the Test Set:

The document mentions "retesting" for discrepant results. For example:

• "Seven Very Major (VM) errors were observed... one E. aerogenes which was resolved upon retest, three P. rettgeri with one of the VM errors resolved upon retest..."
• "...two E. faecium strains, with one M error resolved upon retest and one E. faecalis strain which resolved upon retest."

This suggests a form of post-hoc adjudication or re-testing of discrepant results. The term "resolved" implies that after re-testing, the initial discrepancy either disappeared or was understood in the context of the reference method. There's no explicit mention of an a priori adjudication protocol like 2+1 or 3+1 expert consensus, but rather a re-evaluation of outliers.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance:

This type of study is not applicable to the device described. The Pasco MIC and MIC/ID Panels are in vitro diagnostic devices for antimicrobial susceptibility testing, which typically involve automated or semi-automated reading of growth in wells, not human image interpretation or AI assistance in the way an MRMC study would evaluate. Therefore, no MRMC study was performed, and no effect size would be relevant in this context.

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

Yes, the performance reported (Essential Agreement, Category Agreement, and reproducibility of the device itself) represents standalone performance of the Pasco panels with Cefdinir. While human technicians perform the inoculation and read the results (or interpret automated readers), the "device performance" metrics are for the panel's ability to accurately determine susceptibility, independent of any AI insights or human "improvement." The "Summary/Conclusion of Substantial Equivalence Testing" directly addresses the panel's output against a reference standard.

7. The Type of Ground Truth Used:

The ground truth was established by comparing the Pasco test panel results to a reference panel. This reference panel would typically be a gold standard method for antimicrobial susceptibility testing, such as the broth microdilution or agar dilution methods prescribed by standards organizations like NCCLS (now CLSI). The use of "CDC challenge strains" further reinforces the use of highly characterized reference organisms.

8. The Sample Size for the Training Set:

The document does not provide information on a training set. The described study appears to be the validation or testing phase for the Cefdinir addition. For an in vitro diagnostic device like this, the "training" phase would typically involve the manufacturer's internal development and optimization of the panel's formulation and concentrations using various strains and reference methods, but these details are not part of this 510(k) summary.

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

As no training set is described in the provided text, the method for establishing its ground truth is not available.

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