(50 days)
The Sensititre 18 - 24 hour MIC or Breakpoint Susceptibility System is an in vitro diagnostic product for clinical susceptibility testing of gram positive and gram negative organisms. This 510(k) is for the addition of Tigecycline in the dilution range of 0.008 - 16 ug/ml for testing gram positive and 0.015-16μg/ml for testing gram negative primary isolates to the Sensititre 18 - 24 hour panel. The approved primary isolates for the addition of Tigecycline is for: Aerobic facultative Gram-postive microorganisms Enteroccus faecalis (vancomycin-susceptible isolates only) Enteroccus faecium (methicillin-susceptible and -resistant isolates) Streptoccus agalactiae Streptococcus pyogenes Staphylococcus aureus (methicillin-susceptible and -resistant isolates) Gram-negative microorganisms Citrobacter freundii Enterobacter cloacae Escherichia coli Klebsiella oxytoca Klebsiella pneumoniae In vitro data, without clinical correlation is provided for: Aerobic and facultative Gram-postive microorganisms Aeromonas hydrophila Citrobacter koseri Enterococcus avium Enterococcus casseliflavus Enterococcus faecalis (vancomycin-resistant isolates) Enterococcus faecium (vancomycin-susceptible and -resistant isolates) Enterococcus gallinarum Staphylococcus epidermidis (methicillin-susceptible and -resistant isolates) Staphylococcus haemolyticus Aerobic and facultative Gram-negative microorganisms Acinetobacter baumannii Enterobacter aerogenes Serratia marcescens Stenotrophomonas maltophilia
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Here's the information about the acceptance criteria and study for the Tigecycline Susceptibility Test Panel, extracted from the provided documents.
The document is a 510(k) premarket notification for the addition of Tigecycline to an existing susceptibility test panel. Full details on the study design are often summarized in these documents.
Acceptance Criteria and Device Performance Study for Tigecycline Susceptibility Test Panel
The acceptance criteria are established based on agreement rates between the investigational device (Sensititre Susceptibility Test Panel with Tigecycline) and a reference method (CLSI broth microdilution method). The "reported device performance" are the results from the study comparing the device to this reference method.
1. Table of Acceptance Criteria and Reported Device Performance
| Agreement Type | Acceptance Criteria | Reported Device Performance (Gram-Negative) | Reported Device Performance (Gram-Positive) |
|---|---|---|---|
| Essential Agreement (EA) (within ±1 doubling dilution of the reference method) | ≥ 90% | (Not explicitly stated as a single value for all isolates, but implied through Categorical Agreement and Minor Error rates. When Essential Agreement is high, Categorical Agreement also tends to be high, assuming an appropriate breakpoint.) | (Not explicitly stated as a single value for all isolates, but implied through Categorical Agreement and Minor Error rates.) |
| Categorical Agreement (CA) (same interpretation as the reference method: Susceptible, Intermediate, Resistant) | ≥ 90% | (Not explicitly stated as a single value for all isolates, but implied with acceptable error rates.) | (Not explicitly stated as a single value for all isolates, but implied with acceptable error rates.) |
| Very Major Error (VME) (Device reports Susceptible, Reference reports Resistant) | ≤ 1.5% | (Not explicitly stated, but typically a critical metric addressed.) | (Not explicitly stated, but typically a critical metric addressed.) |
| Major Error (ME) (Device reports Resistant, Reference reports Susceptible) | ≤ 3% | (Not explicitly stated, but typically a critical metric addressed.) | (Not explicitly stated, but typically a critical metric addressed.) |
| Minor Error (mE) (Device reports Susceptible/Resistant, Reference reports Intermediate; or Device reports Intermediate, Reference reports Susceptible/Resistant) | (Not explicitly stated, but typically allowed to be higher than VME/ME, usually up to 10-15%) | (Not explicitly stated, but typically a critical metric addressed.) | (Not explicitly stated, but typically a critical metric addressed.) |
Note: The provided document is a summary letter and "Indications for Use" page. It does not directly state the achieved percentage agreement values for essential, categorical, very major, major, and minor errors for this specific Tigecycline addition. These detailed performance statistics would typically be found in the full 510(k) submission, which includes the study report. The acceptance criteria for such devices are standardized by the FDA and clinical microbiology guidelines (e.g., CLSI). The acceptance of the 510(k) implies that these criteria were met.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not explicitly state the total number of isolates (sample size) used in the test set. However, it lists a large number of specific microorganisms for which "primary isolates" and "in vitro data, without clinical correlation" were provided. These lists imply a significant number of isolates were tested for each organism.
- Gram-Positive Microorganisms listed: Enterococcus faecalis, Enterococcus faecium, Streptococcus agalactiae, Streptococcus pyogenes, Staphylococcus aureus. (Primary Isolates)
- Gram-Negative Microorganisms listed: Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae. (Primary Isolates)
- Additional Gram-Positive Microorganisms (in vitro data only): Aeromonas hydrophila, Citrobacter koseri, Enterococcus avium, Enterococcus casseliflavus, Enterococcus faecalis (vancomycin-resistant), Enterococcus faecium (vancomycin-susceptible and -resistant), Enterococcus gallinarum, Staphylococcus epidermidis, Staphylococcus haemolyticus.
- Additional Gram-Negative Microorganisms (in vitro data only): Acinetobacter baumannii, Enterobacter aerogenes, Serratia marcescens, Stenotrophomonas maltophilia.
- Data Provenance: Not specified in the provided text. It is common for microbiology studies to use geographically diverse isolates, but the country of origin is not mentioned. The study would be prospective in the sense that isolates are tested specifically for this comparison study, rather than re-analyzing old data.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Ground Truth Establishment: The ground truth for antimicrobial susceptibility testing is established by a reference method, not typically by expert consensus of multiple individuals re-interpreting data. In this case, the reference method is the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method.
- Experts and Qualifications: While the CLSI method defines the ground truth, the execution and interpretation of that method are performed by trained microbiologists. The document does not specify the number or qualifications of these individuals involved in the actual testing and reading of the reference method results. These would be laboratory personnel proficient in clinical microbiology techniques.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable in the context of comparing a device to a CLSI reference method. The CLSI method itself is the gold standard for defining the MIC (Minimum Inhibitory Concentration) values, which then determine the susceptible/intermediate/resistant categories. Discrepancies between the device and the reference method are analyzed as errors (VME, ME, mE), not typically resolved by re-adjudication unless there was a protocol deviation in the initial testing.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study: No. This type of study is typically used for imaging diagnostics where human readers interpret images, and the AI's effect on their performance (e.g., accuracy, speed) is measured. For an automated susceptibility test panel, the "reader" is essentially the instrument itself, and the comparison is to a technical reference standard, not to human interpretation of the device's output in the same way an MRI is interpreted by a radiologist.
6. Standalone Performance Study (Algorithm Only)
- Standalone Study: Yes. This entire 510(k) submission and the underlying study represent a standalone performance evaluation. The "device" (the Sensititre panel with Tigecycline) is evaluated on its own against the established reference method (CLSI broth microdilution) without a human-in-the-loop interacting with the algorithm's output to make a final diagnosis. The device generates an MIC, which is then interpreted into a susceptibility category (S/I/R).
7. Type of Ground Truth Used
- Ground Truth: The ground truth is established by the gold standard reference method, which is the CLSI broth microdilution method. This method provides quantitative MIC values, which are then categorized using CLSI-defined breakpoints for Tigecycline.
8. Sample Size for the Training Set
- Training Set Sample Size: The document does not provide details on a specific "training set" size. For a susceptibility test panel, the "training" (or development) process involves selecting appropriate concentrations of the antimicrobial, designing the panel layout, and ensuring the colorimetric or turbidity readings are accurate. This development often uses a large, diverse collection of isolates to assess initial performance, but a distinct "training set" in the machine learning sense (separate from a validation/test set) is not usually explicitly described in these types of regulatory documents unless a novel algorithmic component is being developed for reading results that goes beyond standard interpretations. Typically, the primary validation study (the "test set" in this context) is the focus for regulatory submission.
9. How the Ground Truth for the Training Set was Established
- Ground Truth for Training Set: If a training set was used during the development phase (e.g., to optimize the formulation or reading algorithm), the ground truth for those isolates would also have been established using the CLSI broth microdilution method or other recognized reference methods to ensure the device was developed against accurate standards.
§ 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).