Search Results

The MicroScan® Synergies plus™ 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 anaerobic gram-positive enterococci and staphylococci. After inoculation, panels are incubated for 4.5 - 18 hours at 35℃ +/- 1℃, in a WalkAway® SI, or equivalent, and read by the MicroScan® Instrumentation. Additionally, the panels may be incubated in a non-CO2 incubator and the Antimicrobial Susceptibility Testing (AST) portions can be read visually, according to the Package Insert.

This particular submission is for the addition of the antimicrobial gentamicin, at concentrations of 0.06 to 32 µg/ml Long Dilution Sequence for staphylococci, to the test panel.

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

Staphylococcus species (coagulase-positive and coagulase-negative) .

MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels, utilizing both the MicroScan® Rapid Fluorogenic Identification and Dried Overnight Antimicrobial Susceptibility Testing (AST) technologies, 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 anacrobic Gram-positive enterococci and staphylococci.

The antimicrobial susceptibility tests are miniaturizations of the broth dilution susceptibility test that have been diluted in water and dehydrated. Various antimicrobial agents are diluted in water, buffer, or minute concentrations of broth, to concentrations bridging the range of clinical interest. Panels are rehydrated with Synergies plus" Pos Broth, after inoculation with a standardized suspension of the organism. After incubation in the WalkAway® SI, or equivalent, for 4.5 - 18 hours, the minimum inhibitory concentration (MIC) for the test organism is read by determining the lowest antimicrobial concentration showing inhibition of growth.

The provided 510(k) summary describes the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panels with gentamicin. The study presented aims to demonstrate substantial equivalence to a predicate device.

1. Table of Acceptance Criteria and Reported Device Performance

Note: The FDA document "Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA", dated February 5, 2003, is cited as defining the criteria for "substantial equivalent performance." While the specific numerical acceptance criteria for Essential Agreement are not explicitly stated in the provided text, a common threshold for AST systems is >90% for Essential Agreement. The reported 94.6% meets this implied threshold. "Acceptable" for reproducibility and quality control indicates that these aspects met their predefined criteria, though the specific quantitative metrics for "acceptable" are not detailed.

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

• Test Set Size: The exact number of isolates ("fresh and stock Efficacy isolates and stock Challenge strains") used for the external validation is not specified in the provided text.
• Data Provenance: The data came from an "external validation," implying that the testing was performed outside of Dade Behring's internal facilities. The country of origin is not specified, but given the FDA submission, it is likely the studies were conducted in the US or in a manner compliant with US regulatory requirements. The study used "fresh and stock Efficacy isolates and stock Challenge strains," which suggests a combination of retrospective (stock strains) and prospective (fresh isolates) data collection, though the ratio or specific timing is not detailed.

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

• The ground truth for the test set was established by a "frozen Reference Panel" and "Expected Results determined prior to the evaluation" for Challenge strains. This suggests a comparison against a recognized standard method rather than expert interpretation of raw data. Therefore, the concept of "experts establishing ground truth" in the traditional sense of clinical opinion is not applicable here. The reference panel itself is the gold standard.

4. Adjudication Method for the Test Set

• The study compared the performance of the MicroScan® Synergies plus™ Gram-Positive MIC/Combo Panel against a frozen Reference Panel. This is a direct comparison method, not an adjudication method in the sense of resolving discrepancies between human readers. For the "Challenge strains," their performance was compared to "Expected Results determined prior to the evaluation," which again indicates a comparison to a predefined standard rather than a multi-reader adjudication process.

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, an MRMC comparative effectiveness study was not done. This study evaluates the performance of an automated susceptibility testing system/panel against a reference method, not the impact of AI assistance on human readers.

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

• Yes, a standalone study was performed. The MicroScan® Synergies plus™ system is an automated device designed to determine antimicrobial susceptibility. The study evaluates the performance of this device ("algorithm only" in the sense of the automated panel reading and interpretation) in comparison to the frozen reference panel. The device, after incubation, reads the MIC by "determining the lowest antimicrobial concentration showing inhibition of growth." While human oversight might be involved in initial setup or quality control, the core performance reported (Essential Agreement) is that of the automated system.

7. The Type of Ground Truth Used

• The ground truth used was a "frozen Reference Panel" for efficacy isolates and "Expected Results" for challenge strains. This constitutes a recognized, standardized reference method (broth microdilution in this context) that is considered the gold standard for antimicrobial susceptibility testing.

8. The Sample Size for the Training Set

• The document does not provide information regarding a separate training set or its sample size. This type of submission focuses on the validation of the device against a predicate, typically using a test set against a defined ground truth, rather than detailing the development and training phases of an algorithm.

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

• As no information about a training set is provided, how its ground truth was established is unknown/not applicable from this document.

Ask a specific question about this device