(91 days)
The Sensititre 18-24 hour MIC or Breakpoint Susceptibility System is an in vitro diagnostic product for clinical susceptibility testing of non-fastidious isolates.
This 510(k) is for ciprofloxacin in the dilution range of 0.002-64 ug/mL for testing non-fastidious gram-negative isolates on The Sensititre 18-24 hour MIC or Breakpoint Susceptibility System. Testing is indicated for Enterobacterales and Pseudomonas aeruginosa, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC) webpage.
The Sensititre 18-24 hour MIC or Breakpoint Susceptibility System with Ciprofloxacin in the dilution range of 0.002-64 ug/mL demonstrated acceptable performance with the following organisms:
Enterobacterales (C. freundii, C. koseri, E. cloacae complex, E. coli, K. aerogenes, K. oxytoca, K.pneumoniae, M. morganii, P. mirabilis, P. rettgeri, P. stuartii, P. vulgaris, S. marcescens)
Pseudomonas aeruginosa
Not Found
The provided FDA 510(k) clearance letter (K250990) for "The Sensititre 18-24 hour MIC or Breakpoint Susceptibility System with Ciprofloxacin in the dilution range of 0.002-64 µg/mL" does not include detailed information about the acceptance criteria or the specific study that proves the device meets those criteria. The letter primarily serves as a notification of substantial equivalence and outlines regulatory requirements.
However, based on the nature of the device (Antimicrobial Susceptibility Test) and the context of FDA clearance for such products, we can infer the typical types of acceptance criteria and studies that would have been conducted. Please note that the specific numerical values for acceptance criteria and study details are not present in the provided document and would normally be found in the manufacturer's 510(k) submission summary.
Here's a breakdown of the requested information, with inferred details for sections not explicitly stated:
Acceptance Criteria and Device Performance
Note: The specific acceptance criteria (e.g., % Essential Agreement, % Category Agreement) and the reported device performance for the Sensititre system with Ciprofloxacin are not provided in the FDA clearance letter. For an AST device, these usually revolve around agreement with a reference method.
Inferred Acceptance Criteria and Hypothetical/Typical Reported Performance for AST Devices:
| Metric | Acceptance Criteria (Typical for AST Devices) | Reported Device Performance (Hypothetical/Inferred) |
|---|---|---|
| Essential Agreement (EA) | ≥ 90.0% for each organism/antibiotic combination | ≥ 95.0% |
| Category Agreement (CA) | ≥ 90.0% for each organism/antibiotic combination | ≥ 95.0% |
| Minor Errors (mE) | ≤ 7% | ≤ 5% |
| Major Errors (ME) | ≤ 3% | ≤ 1.5% |
| Very Major Errors (VME) | ≤ 1.5% | ≤ 0.5% |
Explanation of Terms (for AST devices):
- Essential Agreement (EA): The Minimum Inhibitory Concentration (MIC) result of the test device is within ±1 doubling dilution of the reference method's MIC result.
- Category Agreement (CA): The interpretive category (Susceptible, Intermediate, Resistant) assigned by the test device matches the interpretive category assigned by the reference method.
- Minor Errors (mE): One method (test or reference) interprets as Intermediate, and the other interprets as Susceptible or Resistant.
- Major Errors (ME): The test device interprets as Susceptible, but the reference method interprets as Resistant. This is a critical error as it could lead to ineffective treatment.
- Very Major Errors (VME): The test device interprets as Resistant, but the reference method interprets as Susceptible. This is also a critical error as it could lead to unnecessary use of broader-spectrum antibiotics.
Study Details (Inferred/Typical for AST Devices)
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Sample size used for the test set and the data provenance:
- Sample Size (Test Set): Not specified in the clearance letter. For AST devices, test sets typically involve hundreds to thousands of unique isolates for each organism-antibiotic combination to ensure statistical significance across various resistance mechanisms and phenotypes. This would include both common and challenging strains.
- Data Provenance: Not specified. For FDA submissions, the data provenance is usually a mix of prospective and retrospective clinical isolates, often collected from diverse geographical regions (e.g., multiple centers across the United States) to represent a broad range of clinically relevant strains. The clearance letter mentions testing for "Enterobacterales" and "Pseudomonas aeruginosa," indicating a focus on these specific bacterial groups.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not specified. For AST devices, ground truth is typically established by reference laboratory personnel highly experienced in microbiology, particularly in performing and interpreting reference AST methods (e.g., broth microdilution or agar dilution as per CLSI guidelines). These are not usually "experts" in the sense of clinicians reading images, but rather highly skilled microbiologists.
- Qualifications of Experts: Clinical microbiologists, medical technologists, or laboratory scientists with extensive experience (e.g., 5-10+ years) in a clinical microbiology reference laboratory, proficient in CLSI (Clinical and Laboratory Standards Institute) methodologies for antimicrobial susceptibility testing.
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Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Adjudication Method: Not applicable in the traditional sense for AST devices when comparing to a recognized reference method. The "ground truth" (reference method results) is considered definitive. If initial discrepancies occur between the test device and the reference method, these are typically re-tested by the reference method for confirmation rather than adjudicated by human readers. The reference method (e.g., CLSI broth microdilution) is itself the gold standard.
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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:
- MRMC Study: Not applicable. This type of study (MRMC) is relevant for diagnostic imaging devices where human readers interpret images, sometimes with AI assistance. The Sensititre system is an in vitro diagnostic device for antimicrobial susceptibility testing, which directly measures bacterial growth inhibition at various antibiotic concentrations (MICs). It does not involve human "readers" interpreting output in the same way as an imaging device, nor does it typically involve AI assistance in its core mechanism for determining MICs.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Standalone Performance: Yes, the core evaluation of an AST device like Sensititre is a standalone performance study. The device, when operated according to its instructions for use, generates MIC results and interpretive categories. These results are then compared directly to the reference method. There isn't typically a "human-in-the-loop" for the determination of the MIC or category by the device itself, although human laboratory personnel perform the setup and interpretation of the result in the clinical workflow. The performance data presented in the 510(k) submission would reflect this intrinsic performance of the device.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Type of Ground Truth: For AST devices, the ground truth is established by a recognized reference method, typically the CLSI (Clinical and Laboratory Standards Institute) reference broth microdilution method or agar dilution method. This is considered the "gold standard" for determining MICs and susceptibility categories. It is a highly standardized and reproducible laboratory procedure.
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The sample size for the training set:
- Sample Size (Training Set): Not applicable in the same way as for AI/machine learning algorithms. The Sensititre system is a phenotypic AST system, not an AI-based diagnostic algorithm that requires a "training set" of data. Its "training" is inherent in its design and manufacturing, based on established microbiological principles for detecting bacterial growth and inhibition. Any "development" data would be internal to the manufacturer for optimizing plate format, reagent concentrations, and reading algorithms, but not a "training set" in the context of deep learning.
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How the ground truth for the training set was established:
- Ground Truth for Training Set: Not applicable for this type of device. As explained above, the device does not use a "training set" with established ground truth in the AI sense. Its underlying principles are based on microbiological standards and reference methods.
Summary of Information from the FDA Letter:
- Device Name: The Sensititre 18-24 hour MIC or Breakpoint Susceptibility System with Ciprofloxacin in the dilution range of 0.002-64 µg/mL
- Intended Use: In vitro diagnostic product for clinical susceptibility testing of non-fastidious isolates, specifically for Ciprofloxacin in the stated dilution range against Enterobacterales (C. freundii, C. koseri, E. cloacae complex, E. coli, K. aerogenes, K. oxytoca, K.pneumoniae, M. morganii, P. mirabilis, P. rettgeri, P. stuartii, P. vulgaris, S. marcescens) and Pseudomonas aeruginosa.
- Performance: "demonstrated acceptable performance" (no specific metrics or values provided in the clearance letter).
To obtain the detailed acceptance criteria and study specifics, one would need to review the manufacturer's 510(k) summary, which is typically a public document available through the FDA's 510(k) database.
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).