(26 days)
The Sofia 2 SARS Antigen+ FlA is a lateral flow immunofluorescent sandwich assay that is used with the Sofia 2 instrument for the rapid, qualitative detection of SARS-CoV-2 nucleocapsid protein antigens directly in anterior nasal swab specimens from individuals with signs and symptoms of upper respiratory infection (i.e., symptomatic) when testing is started within 6 days of symptom onset. The test is intended for use as an aid in the diagnosis of SARS-CoV-2 infections (COVID-19) in symptomatic individuals when either: tested at least twice over three days with at least 48 hours between tests; or when tested once, and negative by the Sofia 2 SARS Antigen+ FIA and followed up with a molecular test.
The test does not differentiate between SARS-CoV and SARS-CoV-2.
A neqative test result is presumptive, and it is recommended these results be confirmed by a molecular SARS-CoV-2 assay.
Positive results do not rule out co-infection with bacteria or other viruses and should not be used as the sole basis for treatment or other patient management decisions.
Performanc characteristics for SARS-CoV-2 were established during the 2021-2022 SARS-CoV-2 pandemic when SARS CoV 2 Omicron was the predominant SARS-CoV-2 variant in circulation. When other SARS-CoV-2 virus variant are emerging, performance characteristics may vary.
This test is intended for prescription use only and can be used in Point-of-Care settings.
Sofia 2 SARS Antigen+ FIA Control Swab Set:
The Sofia 2 SARS Antigen+FIA Control Swabs are intended to be used as quality control samples with the Sofia 2 SARS Antigen+ FIA and are representative of positive and negative test samples. These Controls may be used to demonstrate that the reagents and assay procedure perform properly.
The Sofia 2 SARS Antigen+FIA is based upon a lateral flow technology that employs immunofluorescence technology in a sandwich design that is used with Sofia 2 to detect nucleocapsid protein from the SARS-CoV-2 virus in human anterior nasal swab specimens.
The patient sample is placed in the Reagent Tube, during which time the virus particles in the sample are disrupted, exposing internal viral nucleoproteins. After disruption, the sample is dispensed into the Test Cassette sample well. The Test Strip is composed of the following biochemical components dried and immobilized onto the nitrocellulose membrane: 1) sample pad that receives the specimen: 2) a label pad that contains detection fluorescent micro-particles, coated with monoclonal antibodies that are specific for SARS-CoV-2 nucleocapsid antigen; 3) embedded monoclonal antibodies specific for SARS-CoV-2 nucleocapsid antigen to capture the antigen-microparticle complex at the tocation. The sample pad facilitates migration of the sample fluid across the nitrocellulose strip into the absorbent pad (See Figure 4-1 in attachment). The test strip also contains a desiccant that does not participate in the assay but serves as a stabilizing agent during storage.
Sample is applied to in the sample well and migrates through a test strip, then passes through the test and control lines. If SARS-CoV-2 viral antigen is present, they will be bound by the fluorescent microparticles io the label pad reqion, forming an antigen-microparticle complex.
The test line is coated with monoclonal antibodies that are specific to SARS-CoV-2 nucleocapsid antigen and is intended to capture the antigen-microparticle complex. If SARS-CoV-2 viral antigen is not present, the fluorescent microparticles will not be trapped by the capture antibodies nor detected by Sofia 2.
The Sofia 2 SARS Antigen+ FIA employs antibody tagged microparticles dyed with a fluorescent compound, to be detected and read by the Sofia 2 reader instrument. The Sofia 2 analyzers automatically scan/image the test strip, collect and analyze the fluorescence data, and report the result as either positive, negative, or invalid.
Additionally, the Sofia 2 Antigen+ FIA utilizes a reference line for the Sofia 2 reader (to locate the test line and negative control line) and a procedural control (to assess for sample presence and adequate sample flow). No colored lines will be visible in the test window of the fluorescent assay cassette, thereby preventing visual interpretation of the test results. The operator must use the Sofia 2 analyzer to obtain a test result.
The Sofia 2 SARS Antigen+ FIA Control Swabs are intended to be used as quality control samples representative of positive and neqative test samples, to demonstrate that the reagents are that the assay procedure is correctly perform.
This document is a 510(k) Premarket Notification from the FDA regarding the Sofia 2 SARS Antigen+ FIA. It primarily details the device's indications for use, its description, and a comparison to a legally marketed predicate device.
Here's an analysis of the provided information to address your request:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in terms of performance metrics (e.g., sensitivity, specificity thresholds) for the currently reviewed device (K233688). This submission (K233688) is for a modification to the labeling of an already cleared device (DEN220039). The core performance characteristics were established during the clearance of the predicate device (DEN220039).
The "510(k) Summary" section explicitly states under "Non-Clinical and/or Clinical Tests Summary & Conclusions": "Not applicable." This indicates that no new performance studies were conducted or provided with this specific submission because the design, material, chemical composition, and principle of operation are unchanged from the predicate device. The changes are limited to a minor revision of the intended use statement on labeling.
Therefore, performance data to directly prove acceptance criteria for this specific submission is not provided in this document. The document refers to the established performance characteristics from the predicate device, stating: "Performanc characteristics for SARS-CoV-2 were established during the 2021-2022 SARS-CoV-2 pandemic when SARS CoV 2 Omicron was the predominant SARS-CoV-2 variant in circulation."
If we were to infer the implied acceptance criteria from the predicate device's clearance, it would be that the device performs "as safe, as effective, and performs as well as the predicate device." However, no specific numerical performance metrics are listed in this document.
2. Sample Size Used for the Test Set and Data Provenance
As stated above, no new performance studies were conducted for this specific submission (K233688). The document explicitly states "Not applicable" for clinical tests. Therefore, there is no sample size for an additional test set, nor new data provenance provided here. Performance characteristics were established during the 2021-2022 SARS-CoV-2 pandemic for the predicate device.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
Since no new studies were conducted, this information is not provided in the document.
4. Adjudication Method for the Test Set
Since no new studies were conducted, this information is not provided in the document.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No MRMC study is mentioned or implied for this submission. The device is an in vitro diagnostic (IVD) rapid antigen test read by an instrument (Sofia 2 analyzer), not typically involving multiple human readers for interpretation in the same way an imaging AI would. The Sofia 2 analyzer automatically scans, collects, analyzes fluorescence data, and reports results as positive, negative, or invalid, preventing visual interpretation.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, this device inherently operates in a "standalone" fashion as an algorithm-only device in terms of result interpretation. The Sofia 2 analyzer processes the test strip by detecting and reading fluorescent microparticles, analyzing the fluorescence data, and automatically reporting the result without human interpretation of the signal on the test strip. The human interaction is limited to collecting the sample, performing the assay steps, and reading the final result from the instrument.
7. The Type of Ground Truth Used
The document indicates the test is intended as an aid in diagnosis, and negative test results are presumptive and "recommended these results be confirmed by a molecular SARS-CoV-2 assay." This strongly implies that the ground truth for establishing the device's performance characteristics (for the predicate device) would have been molecular SARS-CoV-2 assays (e.g., RT-PCR), which are considered the gold standard for SARS-CoV-2 detection.
8. The Sample Size for the Training Set
No information about a training set or its sample size is provided in this document, as no new performance studies were conducted for this submission. The initial development and training (if applicable, for the Sofia 2 analyzer's signal processing algorithm) would have occurred prior to the predicate device's clearance.
9. How the Ground Truth for the Training Set Was Established
Since no information on a training set is provided, the method for establishing its ground truth is also not mentioned. It is likely that for the predicate device, if machine learning was involved in interpreting the fluorescent signal, the training data's ground truth would have been established against molecular SARS-CoV-2 assays, similar to the test set ground truth.
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