(189 days)
The Sofia Strep A FIA employs immunofluorescence technology to detect Group A Streptococcal antigens from throat swabs of symptomatic patients. All negative test results should be confirmed by bacterial culture because negative results do not preclude Group A Strep infection and should not be used as the sole basis for treatment. The test is intended for professional and laboratory use as an aid in the diagnosis of Group A Streptococcal infection.
The Sofia Strep A FIA employs immunofluorescence technology that is used with the Sofia Analyzer to detect Group A Streptococcal antigens. The Sofia Strep A FIA is a lateral-flow immunoassay that uses polyclonal antibodies that are specific for Group A Streptococcal antigens. Throat swab specimens are used for this test. The patient specimen is placed in the Reagent Tube, during which time the bacteria in the specimen are disrupted, exposing Group A Streptococcal antigens. After disruption, the specimen is dispensed into the cassette sample well. From the sample well, the specimen migrates through a test strip containing various unique chemical environments. If the Group A Streptococcal antigen is present, they will be trapped in a specific location. Note: Depending upon the user's choice, the cassette is either placed inside of the Sofia Analyzer for automatically timed development (Walk Away Mode) or placed on the counter or bench top for a manually timed development and then placed into the Sofia Analyzer to be scanned (Read Now Mode). The Sofia Analyzer will scan the test strip and measure the fluorescent signal by processing the results using method specific algorithms. The Sofia Analyzer will display the test results (Positive, Negative, or Invalid) on the screen. The results can also be automatically printed on an integrated printer if this option is selected.
Here's an analysis of the provided text regarding the acceptance criteria and study for the Sofia® Strep A FIA and Sofia Analyzer:
Note: The provided text lacks the explicit "acceptance criteria" and the full "study that proves the device meets the acceptance criteria" in terms of specific performance targets (e.g., sensitivity, specificity thresholds). It outlines the studies performed and then states a conclusion of "substantial equivalence" based on these studies. Therefore, the table below will present the reported device performance, and the "acceptance criteria" part will reflect an inferred benchmark based on the predicate device and the general aim of demonstrating substantial equivalence.
Acceptance Criteria and Device Performance Study for Sofia® Strep A FIA and Sofia Analyzer
1. Table of Acceptance Criteria and Reported Device Performance
| Metric | Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|
| Sensitivity | To be substantially equivalent to the predicate device (QuickVue Dipstick Strep A Test, K011097) in detecting Group A Streptococcal antigens. | "A multi-center field clinical study was undertaken to document the performance characteristics of the test. Sensitivity and specificity were calculated using throat swab specimens." (Actual numerical values for sensitivity are not provided in this summary.) |
| Specificity | To be substantially equivalent to the predicate device (QuickVue Dipstick Strep A Test, K011097) in distinguishing Group A Streptococcal antigens from other substances. | "A multi-center field clinical study was undertaken to document the performance characteristics of the test. Sensitivity and specificity were calculated using throat swab specimens." (Actual numerical values for specificity are not provided in this summary.) |
| Reproducibility | Consistent results across different operators, laboratories, and varying concentrations. | "A reproducibility study was performed to demonstrate intra- and inter-operator reproducibility and intra- and inter-laboratory reproducibility with a panel of test samples at various Strep A concentrations." (Specific results or acceptance thresholds are not provided.) |
| Analytical Studies | Satisfactory performance in various analytical aspects (e.g., accurate detection limit, no significant cross-reactivity, stability under various conditions). | "Analytical studies included Limit of Detection, analytical inclusivity, cross-reactivity, interfering substances, operating temperature, transport stability, inter-analyzer precision, calibration cycle, and various flex studies." (Specific results or acceptance thresholds are not provided.) |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: The document mentions "A multi-center field clinical study" and "throat swab specimens" for sensitivity and specificity calculations. However, the exact number of specimens or sample size used for the clinical test set is not specified in this summary.
- Data Provenance: The document states "A multi-center field clinical study." The country of origin is not explicitly stated, but being a 510(k) submission to the FDA, it is highly probable that at least a significant portion, if not all, of the clinical data was collected in the United States. The study was prospective, as it was a "field clinical study" to document performance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- The document does not explicitly state the number of experts used to establish the ground truth or their specific qualifications (e.g., "radiologist with 10 years of experience").
- However, for Strep A immunological tests, the ground truth is typically established by bacterial culture, which is considered the gold standard for diagnosis. Therefore, experts involved would likely be clinical microbiologists or laboratory personnel experienced in bacterial culture techniques and interpretation.
4. Adjudication Method for the Test Set
- The document does not specify an adjudication method (e.g., 2+1, 3+1, none) for the test set. Given that the ground truth for Strep A is generally established by bacterial culture, a consensus among human readers for image interpretation (as implied by adjudication in radiology studies) is not typically applicable in this context. The culture result itself serves as the definitive reference.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and the effect size of how much human readers improve with AI vs without AI assistance
- No, an MRMC comparative effectiveness study was not done as described for AI assistance in image interpretation. This device is an in vitro diagnostic (IVD) test that automates the reading of a lateral-flow immunoassay. It does not involve human readers interpreting images with or without AI assistance in the traditional sense of an MRMC study. The Sofia Analyzer is the "AI" or automated reader, replacing manual visual interpretation.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, a standalone study was done. The Sofia Strep A FIA, when used with the Sofia Analyzer, is designed for automated analysis. The "Read Results" feature states "Read results on instrument screen or print with optional printer" and "Automated Analysis: Yes." The analytical and clinical studies were performed to demonstrate the performance of this automated system directly, without a human-in-the-loop for result interpretation, beyond simply reading the result the analyzer provides.
7. The Type of Ground Truth Used
- The ground truth used for establishing clinical performance (sensitivity and specificity) was bacterial culture. The intended use statement explicitly directs: "All negative test results should be confirmed by bacterial culture because negative results do not preclude Group A Strep infection and should not be used as the sole basis for treatment." This indicates that bacterial culture is the definitive reference method.
8. The Sample Size for the Training Set
- The document does not provide information on the sample size for a training set. For IVD devices like this, the "algorithm" is embedded in the Sofia Analyzer. While the algorithms would have been developed and refined using internal data, this summary focuses on the validation of the final device within clinical and analytical studies, not the development phase.
9. How the Ground Truth for the Training Set Was Established
- As with the training set sample size, the document does not provide details on how the ground truth for any potential training set was established. Assuming there was an internal development phase, the ground truth for training data would likely also have been established using bacterial culture as the gold standard, similar to the method for the clinical validation studies.
§ 866.3740
Streptococcus spp. serological reagents.(a)
Identification. Streptococcus spp. serological reagents are devices that consist of antigens and antisera (excluding streptococcal exoenzyme reagents made from enzymes secreted by streptococci) used in serological tests to identifyStreptococcus spp. from cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genusStreptococcus and provides epidemiological information on these diseases. Pathogenic streptococci are associated with infections, such as sore throat, impetigo (an infection characterized by small pustules on the skin), urinary tract infections, rheumatic fever, and kidney disease.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.