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The VITEK® Gram Negative Susceptibility Test is intended to be used with the VITEK® System for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant aerobic gram-negative bacilli, Staphylococcus spp., Enterococcus spp., Streptococcus agalactiae, and S. pneumoniae. VITEK® Gram Negative Ertapenem is designed for antimicrobial susceptibility testing of Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Citrobacter koseri, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella oxytoca (excluding ESBL producing strains), Morganella morganii, Proteus mirabilis, Proteus vulgaris and Serratia marcescens. VITEK Gram Negative Ertapenem is for qualitative testing only. It is intended for use with the VITEK System as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents.

VITEK® Gram Negative Ertapenem is designed for antimicrobial susceptibility testing of Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Citrobacter koseri, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella oxytoca (excluding ESBL producing strains), Morganella morganii, Proteus mirabilis, Proteus vulgaris and Serratia marcescens. It is intended for use with the VITEK® System as a laboratory and in the determination of in vitro susceptibility to antimicrobial agents. The antimicry ial presented in VITEK GNS Cards is in concentrations equivalent by efficacy to atandard method concentrations in mcg/ml. The VITEK GNS Cards are essentially miniturized versions of the doubling dilution technique for determining the minimum in hilitory concentration (MIC) microdilution methodology.

Here's a breakdown of the acceptance criteria and study details for the VITEK® Gram Negative Ertapenem device:

1. Acceptance Criteria and Reported Device Performance

Explanation of Acceptance Criteria (Inferred):
The document states that the device "demonstrated substantially equivalent performance when compared with the NCCLS reference agar dilution method, as defined in the FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems." While the specific numerical acceptance criteria (e.g., minimum percentage for Category Agreement, Essential Agreement) are not explicitly listed in the provided text, the phrase "substantially equivalent" and the reference to FDA guidance imply that the device needed to meet established performance standards for AST systems, which typically include high percentages for categories like "Category Agreement" and "Essential Agreement" when compared to a gold standard. The reported 98.7% Category Agreement indicates that the device met these implicit high standards.

2. Sample Size and Data Provenance for the Test Set

• Sample Size for Test Set: An "external evaluation was conducted with fresh and stock clinical isolates and stock challenge strains." The exact number of isolates used is not specified in the provided text.
• Data Provenance: The text does not explicitly state the country of origin. The use of "fresh and stock clinical isolates" suggests real-world clinical samples, and "stock challenge strains" are typically well-characterized, standardized strains used for rigorous testing. The application is submitted by bioMérieux, Inc. in Hazelwood, MO, USA, and reviewed by the FDA, suggesting the study was likely conducted with data relevant to the US regulatory context.
• Retrospective or Prospective: Not explicitly stated, however, "fresh clinical isolates" usually imply a prospective collection once the study began, while "stock clinical isolates" and "stock challenge strains" could be either, but are often used in a retrospective manner from existing collections.

3. Number of Experts and Qualifications for Ground Truth for the Test Set

• Number of Experts: Not applicable/not specified.
• Qualifications of Experts: Not applicable.

Explanation: The ground truth for this device is based on a laboratory reference method (NCCLS agar dilution method), not expert human interpretation. Therefore, experts are not used to establish the ground truth in the context of this study.

4. Adjudication Method for the Test Set

• Adjudication Method: Not applicable. The "ground truth" is a laboratory reference method (NCCLS agar dilution method), so there is no need for expert adjudication.

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

• Was an MRMC study done? No.
• Effect size of human readers with vs. without AI assistance: Not applicable.

Explanation: This device is a fully automated antimicrobial susceptibility testing system, without direct human-in-the-loop diagnostic interpretation in the traditional sense. The comparison is between the automated system and a reference laboratory method, not between human readers with and without AI assistance for interpretation.

6. Standalone (Algorithm Only) Performance Study

• Was a standalone study done? Yes. The study evaluates the performance of the VITEK® Gram Negative Ertapenem system "when compared with the NCCLS reference agar dilution method." This is a direct comparison of the device's output (algorithm only) against a gold standard, without human intervention in the interpretation process of the device's results.

7. Type of Ground Truth Used

• Type of Ground Truth: The ground truth used is the NCCLS reference agar dilution method. This is a laboratory-based, objective, and standardized methodology for determining minimum inhibitory concentrations (MICs) of antimicrobials.

8. Sample Size for the Training Set

• Sample Size for Training Set: The provided text does not specify the sample size for the training set. It focuses on the external evaluation (test set).

9. How Ground Truth for the Training Set Was Established

• How Ground Truth for Training Set Was Established: The text does not specify how the ground truth for any potential training set was established. However, given the nature of the device and the reference method used for the test set, it is highly probable that if a training set was used (which is standard for automated systems), its ground truth would also have been established using similar NCCLS reference methods or other standardized laboratory techniques.

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