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The BD Veritor™ System for Rapid Detection of Flu A+B CLIA-Waived Kit is a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral nucleoprotein antigens from nasal and nasopharyngeal swabs of symptomatic patients. The BD Veritor™ System for Rapid Detection of Flu A+B CLIA-Waived Kit (also referred to as the BD Veritor System and BD Veritor System Flu A+B) is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single device. The test is to be used as an aid in the diagnosis of influenza A and B viral infections. A negative test is presumptive, and it is recommended that these results be confirmed by viral culture or an FDA-cleared influenza A and B molecular assay. Negative test results do not preclude influenza viral infection and should not be used as the sole basis for treatment or other patient management decisions. The test is not intended to detect influenza C antigens.

Performance characteristics for influenza A and B were established during January through March of 2011 when influenza viruses A/2009 H1N1, A/H3N2, B/Victoria lineage, and B/Yamagata lineage were the predominant influenza viruses in circulation according to the Morbidity and Mortality Weekly Report from the CDC entitled "Update: Influenza Activity-United States, 2010-2011 Season, and Composition of the 2011-2012 Influenza Vaccine." Performance characteristics may vary against other emerging influenza viruses.

If infection with a novel influenza virus is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions for novel virulent influenza viruses and sent to the state or local health department for testing. Virus culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.

The BD Veritor™ System for Rapid Detection of Flu A+B CLIA Waived Kit is a rapid chromatographic immunoassay for the direct and qualitative detection of influenza A and B viral antigens from nasopharyngeal and nasal swabs of symptomatic patients. The test is to be used as an aid in the diagnosis of influenza A and B viral infections. It is a differentiated test, such that influenza A viral antigens can be distinguished from influenza B viral antigens from a single processed sample using a single test device. Negative test results do not preclude influenza viral infection and should not be used as the sole basis for treatment or other management decisions. All negative test results should be confirmed by another methodology, such as a nucleic acid-based method.

BD Veritor™ System Flu A+B test devices are interpreted by a BD Veritor™ Plus Analyzer. When using the BD Veritor™ Plus Analyzer, workflow steps depend on the selected operational mode and the Analyzer configuration settings. In Analyze Now mode, the instrument evaluates assay devices after manual timing of their development. In Walk Away mode, devices are inserted immediately after application of the specimen, and timing of assay development and analysis is automated.

The BD Veritor™ System Flu A+B CLIA-Waived Kit is an immuno-chromatographic assay for detection of influenza A and B viral antigens in samples processed from respiratory specimens. The viral antigens detected by the BD Flu A+B test are nucleoprotein, not hemagglutinin (HA) or neuraminidase (NA) proteins. Flu viruses are prone to minor point mutations (i.e., antigenic drift) in either one or both of the surface proteins (i.e., HA or NA). The BD Flu A+B test is not affected by antigenic drift or shift because it detects the highly conserved nucleoprotein of the influenza viruses. To perform the test, the patient specimen swab is treated in a supplied reaction tube prefilled with a lysing agent that serves to expose the target viral antigens, and then expressed through a filter tip into the sample well on a BD Veritor"10 Flu A+B test device. Any influenza A or influenza B viral antigens present in the specimen bind to anti-influenza antibodies conjugated to colloidal gold micro-particles on the BD Veritor™ Flu A+B test strip. The antigen-conjugate complex then migrates across the test strip to the capture zone and reacts with either Anti-Flu A or Anti-Flu B antibodies that are immobilized on the two test lines on the membrane.

The BD Flu A+B test device shown in Figure 1 is designed with five spatially distinct zones including positive and negative control line positions, separate test line positions for the target analytes, and a background zone. The test lines for the target analytes are labeled on the test device as 'A' for flu A position, and 'B' for flu B position. The onboard positive control ensures the sample has flowed correctly and is indicated on the test device as 'C'. Two of the five distinct zones on the test device are not labeled. These two zones are an onboard negative control line and an assay background zone. The active negative control feature in each test identifies and compensates for specimen-related, nonspecific signal generation. The remaining zone is used to measure the assay background.

The BD Veritor™ Plus Analyzer is a digital immunoassay instrument that uses a reflectance-based measurement method and applies assay specific algorithms to determine the presence or absence of the target analyte. The Analyzer supports the use of different assays by reading an assay-specific barcode on the test device. Depending on the configuration chosen by the operator, the instrument communicates status and results to the operator via a liquid crystal display (LCD) on the instrument, a connected printer, or through a secure connection to the facility's information system.

In the case of the Flu A + B test, the BD Veritor™ Plus Analyzer subtracts nonspecific signal at the negative control line from the signal present at both the Flu A and Flu B test lines. If the resultant line signal is above a pre-selected assay cutoff, the specimen scores as positive. If the resultant line signal is below the cutoff, the specimen scores as negative. Use of the active negative control feature allows the BD Veritor™ Plus Analyzer to correctly interpret test results that cannot be scored visually because the human eye is unable to accurately perform the subtraction of the nonspecific signal. The measurement of the assay background zone is an important factor during test interpretation as the reflectance is compared to that of the control and test zones. A background area that is white to light pink indicates the device has performed correctly.

The provided text describes a 510(k) premarket notification for modifications to the BD Veritor™ System for Rapid Detection of Flu A+B CLIA-Waived Kit. The current submission (K232434) focuses on changes to the BD Veritor™ Plus Analyzer, not the assay itself. Therefore, the details about acceptance criteria and clinical performance studies relate to the predicate device (K223016) and the assay's original clearance (K180438), as the modifications in K232434 do not impact the assay's analytical or clinical performance.

Here's a breakdown based on the provided input:

1. Table of Acceptance Criteria and Reported Device Performance

The current submission (K232434) is for modifications to the analyzer, not a new or modified assay. Therefore, it does not present new acceptance criteria or device performance data for the assay's diagnostic accuracy. Instead, it relies on the previously established performance of the predicate device (K223016) which itself relies on the performance established in K180438. The acceptance criteria for the current submission are related to the safety and electromagnetic compatibility of the modified analyzer.

Performance Characteristics for Influenza A and B (as established for K180438 / K223016 and referenced here):

The document mentions that performance characteristics for influenza A and B were established during January through March of 2011. While specific sensitivity and specificity values are not provided in this document excerpt, the "Indications for Use" and "Intended Use" sections clearly state that the device is for "direct and qualitative detection of influenza A and B viral nucleoprotein antigens."

2. Sample Size Used for the Test Set and Data Provenance

The provided text does not include the specific sample size for the test set used to establish the clinical performance of the Flu A+B assay, nor does it explicitly state the data provenance (e.g., retrospective or prospective studies) in detail, beyond mentioning:

• "Performance characteristics for influenza A and B were established during January through March of 2011"
• This period corresponded to when "influenza viruses A/2009 H1N1, A/H3N2, B/Victoria lineage, and B/Yamagata lineage were the predominant influenza viruses in circulation" in the United States, according to CDC reports. This implies real-world, clinical data from symptomatic patients in the US during that influenza season was used.

Since the current submission is for analyzer modifications and explicitly states, "Clinical Performance: Clinical performance testing was not required because the changes made to the Analyzer do not have an impact on the assay-specific clinical performance," this information would be found in the original submission (K180438) that cleared the assay.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts

This information is not provided in the given text. It would be part of the detailed clinical study report from the original assay clearance (K180438).

4. Adjudication Method for the Test Set

This information is not provided in the given text. It would be part of the detailed clinical study report from the original assay clearance (K180438).

5. 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

This is not applicable to the BD Veritor System. This device is a rapid chromatographic immunoassay read by a digital analyzer (BD Veritor™ Plus Analyzer), not an AI system designed to assist human readers in interpreting complex images or data. The analyzer automatically interprets the test results based on its algorithms and provides a positive, negative, or invalid result, rather than providing input to a human reader for their interpretation.

6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done

Yes, in essence, the BD Veritor™ Plus Analyzer operates as a standalone algorithm without human-in-the-loop performance for result interpretation. The text states:

• "The Analyzer is a digital immunoassay instrument that uses a reflectance-based measurement method and applies assay specific algorithms to determine the presence or absence of the target analyte."
• "The BD Veritor™ Plus Analyzer subtracts nonspecific signal at the negative control line from the signal present at both the Flu A and Flu B test lines. If the resultant line signal is above a pre-selected assay cutoff, the specimen scores as positive. If the resultant line signal is below the cutoff, the specimen scores as negative."
• "Use of the active negative control feature allows the BD Veritor™ Plus Analyzer to correctly interpret test results that cannot be scored visually because the human eye is unable to accurately perform the subtraction of the nonspecific signal."

This clearly describes an automated interpretation process by the device's algorithms.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The document states, "A negative test is presumptive, and it is recommended that these results be confirmed by viral culture or an FDA-cleared influenza A and B molecular assay." This implies that viral culture or an FDA-cleared influenza A and B molecular assay served as the reference standard (ground truth) for establishing performance characteristics during the original clinical studies.

8. The Sample Size for the Training Set

This information is not provided in the given text, and it's less relevant for an immunoassay where "training data" for a machine learning model might not be explicitly defined in the same way as for complex AI algorithms. For immunoassays, the "training" involves optimizing the assay reagents and conditions, and setting cutoff values, which are then validated with clinical samples.

9. How the Ground Truth for the Training Set Was Established

This information is not provided in the given text. As mentioned above, the concept of a "training set ground truth" might not apply directly in the traditional sense for this type of immunoassay. Instead, the ground truth for establishing performance (and implicitly for setting cutoffs) would be established using the reference methods mentioned in point 7.

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