(88 days)
VITEK® 2 AST-Gram Negative Amikacin is designed for antimicrobial susceptibility testing of Gram Negative bacilli and is intended for use with the VITEK® 2 Compact Systems as a laboratory aid in the determination of in vitro susceptibility to antimicrobial agents. VITEK® 2 AST-Gram Negative Amikacin is a quantitative test. Amikacin has been shown to be active against most strains of the microorganisms listed below, according to the FDA label for this antimicrobial.
Active in vitro and in clinical infections: Pseudomonas species Escherichia coli Proteus mirabilis Klebsiella species Enterobacter species Serratia species Acinetobacter species (excluding A. baumannii Complex)
In vitro data available but clinical significance unknown: Citrobacter freundii
The VITEK® 2 Antimicrobial Susceptibility Test (AST) is intended to be used with the VITEK® 2 Systems for the automated quantitative or qualitative susceptibility testing of isolated colonies for the most clinically significant acrobic gram-negative bacilli, Staphylococus spp., Enterococcus spp., Streptococcus spp. and clinically significant yeast.
The antimicrobial presented in VITEK® 2 AST-GN Cards is in concentrations equivalent by efficacy to standard method concentrations in mcg/ml. The VITEK® 2 AST Cards are essentially miniaturized versions of the doubling dilution technique for determining the minimum inhibitory concentration (MIC) microdilution methodology.
The isolate to be tested is diluted to a standardized concentration in 0.45 - 0.50% saline before being used to rehydrate the antimicrobial medium within the card. The VITEK® 2 automatically fills, seals and places the card into the incubator/reader. The VITEK® 2 Compact has a manual filling and sealing operation. The VITEK® 2 monitors the growth of each well in the card over a defined period of time (up to 18 hours). At the completion of the incubation cycle, a report is generated that contains the MIC value along with the interpretive category result for each antimicrobial contained on the card.
The provided document is a 510(k) premarket notification for a medical device called "VITEK® 2 AST-GN Amikacin," an antimicrobial susceptibility testing system. While it specifies the device's performance against certain acceptance criteria, it does not describe a study involving human readers or AI assistance in the context of diagnostic imaging. Therefore, I will extract relevant information about the non-AI device's performance and address the provided questions within that scope, noting where the information is not applicable to an AI/human reader study.
Here's a breakdown of the requested information based on the provided document:
Acceptance Criteria and Device Performance (for a non-AI diagnostic device)
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Essential Agreement (EA) with reference method | 94.9% overall Essential Agreement with the CLSI broth microdilution reference method. |
| Category Agreement (CA) with reference method | 98.4% overall Category Agreement with the CLSI broth microdilution reference method. |
| Reproducibility | Acceptable results. (Specific metrics not quantitatively reported in this summary, but stated as acceptable). |
| Quality Control | Acceptable results. (Specific metrics not quantitatively reported in this summary, but stated as acceptable). |
Study Details (for VITEK® 2 AST-GN Amikacin)
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Sample sizes used for the test set and the data provenance:
- Test Set Sample Size: The document mentions that an "external evaluation was conducted with fresh and stock clinical isolates, as well as a set of challenge strains." It doesn't provide a specific numerical sample size for the test set, but implies a combination of clinical isolates and challenge strains were used.
- Data Provenance: Not explicitly stated, but "clinical isolates" typically implies patient samples. The document does not specify the country of origin or if the data was retrospective or prospective. It refers to a "Premarket Notification (510[k])" which typically involves prospective studies for new devices, but this is not explicitly stated for the data collection itself.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This is not applicable to the VITEK® 2 AST-GN Amikacin device study as described. The ground truth for antimicrobial susceptibility testing is established via a "CLSI broth microdilution reference method," not through human expert consensus in the way a diagnostic imaging study would be. Therefore, no information is provided on expert numbers or qualifications for ground truth establishment.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not applicable. The ground truth is a laboratory reference method, not an adjudicated read from experts.
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If a multi-reader multi-case (MRMC) comparative effectiveness study was done, and what was the effect size of how much human readers improve with AI vs. without AI assistance:
- Not applicable. This study pertains to an automated antimicrobial susceptibility testing system, not an AI-assisted diagnostic imaging system with human readers. No MRMC study was performed, and thus no effect size on human reader improvement with AI assistance is reported.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, this study is essentially a standalone performance evaluation of the VITEK® 2 AST-GN Amikacin system against a reference method. The device itself is an automated system; it's not designed to assist a human in interpreting results but rather to provide the results directly. Its performance (Essential Agreement and Category Agreement) is reported as standalone.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth used was the CLSI broth microdilution reference method (Clinical and Laboratory Standards Institute). This is considered the gold standard for determining minimum inhibitory concentrations (MICs) of antimicrobials.
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The sample size for the training set:
- The document describes a "Premarket Notification (510[k])" and refers to "external evaluation" and "clinical isolates" for the test set. It does not explicitly mention a separate "training set" or its size. In the context of traditional diagnostic devices (not AI/ML, which often have distinct training and testing phases), the "training" might be considered part of the device's development and internal validation, which isn't detailed in this summary.
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How the ground truth for the training set was established:
- Not applicable, as a distinct training set with its own ground truth establishment is not described for this type of device and study within the provided summary. The device's underlying methodology (miniaturized doubling dilution) is based on established principles, and validation is done against the CLSI reference method.
§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.
(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”