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MicroScan® Synergies plus™ Gram-Negative 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 anaerobic Gram-Negative bacilli (Enterobacteriaceae, glucose non-fermenters, and non-Enterobacteriaceae glucose fermenters. After inoculation, panels are read on the WalkAway® SI System or equivalent (upgraded WalkAway® 40 or WalkAway® 96) according to the Package Insert.

This particular submission is for the antimicrobial Piperacillin on the Synergies plus" Gram-Negative MIC/Combo Panels.

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

Escherichia coli Enterobacter spp. Klebsiella spp. (except Klebsiella oxytoca) Proteus spp. (except Proteus mirabilis) Providencia rettgeri Pseudomonas spp Serratia spp Shigella spp Salmonella spp. Yersinia spp.

The MicroScan® Synergies plus™ Gram-Negative with Piperacillin is not intended for use with:

Acinetobacter spp. Citrobacter spp. Klebsiella oxytoca Morganella morganii Proteus mirabilis

MicroScan® rapID/S plus™ Gram-Negative MIC/Combo Panels are designed for use in acterming quantitative and/or qualitative antimicrobial agent susceptibility of colonies grown on solid nedia of rapidly growing aerobic and facultative anaerobic gram-negative bacilli. The MicroScan® rapIDS play™ (171 growing aeroon and faculture and on the WalkAway S7 System or equivalent (upgraded WalkAway® 40 or WalkAway® 96 instruments).

The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility to the may The andilited in Mueller-Hinton Broth to concentrations bridging the range of clinical interest and are becal unded in micro-titer wells in dried form. rapID/S plus™ panels are inoculated with a presented in inicio-nier wells in and incubated at 35°C in the WalkAway® S7 System or equivalent standardized suspension of the organism and interest organism is determined by the lowest antimicrobial concentration showing inhibition of growth.

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

Acceptance Criteria and Device Performance

The document doesn't explicitly state a table of "acceptance criteria" with numerical targets for Essential Agreement (EA) or Category Agreement (CA) prior to presenting results, which is common in more recent FDA submissions. Instead, it states that the external evaluation was designed to "confirm the acceptability of the proposed rapID/S plus™ Gram-Negative MIC/Combo Panel with Piperacillin standards of the Panel, as defined in the FDA DRAFT document 'Guidance on Review Criteria for Assessment of Antimicrobial Susceptibility Devices'". The specific numerical criteria from this draft guidance are not provided in this document.

However, the reported device performance is:

Note: The document refers to "Essential Agreement" but does not explicitly mention "Category Agreement." It implies that achieving an acceptable EA percentage is the primary measure of performance from this summary.

Study Information

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

• Test Set Organisms: The external evaluation used "fresh and stock Efficacy isolates and stock Challenge strains."
  • The "Efficacy isolates" are likely the clinical isolates, and the "Challenge strains" are likely isolates with known resistance mechanisms or difficult-to-test characteristics.
• Sample Size: The document does not specify the exact number of isolates (sample size) used in the test set.
• Data Provenance: Not explicitly stated (e.g., country of origin, retrospective/prospective). However, the use of "fresh and stock Efficacy isolates" suggests a mix, and "stock Challenge strains" are typically laboratory-maintained. It doesn't indicate if these were prospectively collected patient samples or geographically diverse.

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

• The ground truth for the test set was established by an "NCCLS frozen Reference panel." This implies a standardized reference method rather than individual human experts.
• Therefore, information on the number or qualifications of experts for establishing ground truth is not applicable in the traditional sense, as it relies on a reference method.

4. Adjudication method for the test set:

• Not applicable. The ground truth was established by comparison to an "NCCLS frozen Reference panel," which is a standardized method, not a human consensus process.

5. If a multi-reader, multi-case (MRMC) comparative effectiveness study was done, and if so, what was the effect size of how much human readers improve with AI vs. without AI assistance:

• No. This is an in vitro diagnostic device for antimicrobial susceptibility testing, which directly measures bacterial responses to antibiotics. It is not an imaging device or a decision support AI system meant to assist human readers, so an MRMC comparative effectiveness study is not applicable.

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

• Yes, this is essentially a standalone performance study. The device itself (MicroScan® Synergies plus™ Gram-Negative MIC/Combo Panels read by the WalkAway® System) generates the susceptibility results based on its internal processes and measurements. The "Overall Essential Agreement 94.4%... when compared with the frozen Reference panel" directly reflects this standalone performance against a gold standard.

7. The type of ground truth used:

• Reference Method (NCCLS frozen Reference panel). This is a highly standardized and accepted method for determining antimicrobial susceptibility, serving as the gold standard for comparison in these types of studies.

8. The sample size for the training set:

• Not explicitly stated in the provided text. The document describes the external evaluation (test set) but does not mention a distinct "training set" or its size for the development of the device or its interpretive algorithms. For this type of in vitro diagnostic device, the "training" often involves extensive empirical testing and optimization during development, rather than a separate, formally delineated training set as understood in current machine learning paradigms.

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

• Not explicitly stated in the provided text. As a "training set" is not mentioned, the method for establishing its ground truth is also not detailed. Device development typically involves internal testing against reference methods to refine specifications and performance, but specific details on a formal training set and its ground truth establishment are absent.

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