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The Alere BinaxNOW® Influenza A & B Card 2 is an in vitro immunochromatographic assay for the qualitative detection of influenza A and B nucleoprotein antigens in nasopharyngeal (NP) swab and nasal swab specimens. It is intended to aid in the rapid differential diagnosis of influenza A and B viral infections. Negative test results are presumptive and should be confirmed by cell 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. Alere BinaxNOW® Influenza A & B Card 2 must be read by the Alere™ Reader.

Performance characteristics for influenza A were established during the 2015-2016 influenza season when influenza A/H3N2 and A/H1N1 pandemic were the predominant influenza A viruses in circulation. When other influenza A viruses are emerging, performance characteristics may vary.

If infection with a novel influenza A 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 state or local health department for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.

The Alere BinaxNOW® Influenza A & B Card 2 is an immunochromatographic membrane assay that detects influenza type A and B nucleoprotein antigens in respiratory specific antibodies and a control antibody are immobilized onto a membrane support as three distinct lines and combined with other reagents/pads to construct a test strip is mounted inside a cardboard, book-shaped hinged test card.

Swab specimens require a sample preparation step, in which the sample is eluted off the swab into Elution Solution. Sample is added to the test strip and the test card is closed. Test results are interpreted at 15 minutes based on the presence or absence of Sample Lines. Alere BinaxNOW® Influenza A & B Card 2 test results must be read by the Alere™ Reader.

The Alere™ Reader is an easy to use bench top instrument that can be used near patient and in laboratory settings which will interpret, capture and transmit test results. The Alere™ Reader is a camera based instrument that detects the presence and identity of the Alere BinaxNOW® Influenza A& B Card 2 assay, analyzes the intensity of the test and control lines and displays the results (positive or invalid) on a display screen. The screen is intended as a means of user interface informing the user how to operate the Reader and to display test results, including any errors. Data can be retrieved and downloaded by the operator at any time after testing and uploaded to the hospital LIS/LIM system, if desired. Operator ID and Subject ID can be entered manually or via the provided barcode scanner. An external printer can be attached via USB to the Alere™ Reader to print test results.

This is a 510(k) premarket notification for a software modification to the Alere™ Reader, which is used with the Alere BinaxNOW® Influenza A & B Card 2 assay. The purpose of the submission is to introduce a "Walk Away" mode to the reader's software, alongside other minor enhancements. The underlying immunochromatographic assay (Alere BinaxNOW® Influenza A & B Card 2) itself remains unchanged.

Here's an analysis of the provided text in relation to your questions:

1. Table of Acceptance Criteria and Reported Device Performance

The submission focuses on a software modification to the Alere™ Reader. It explicitly states: "There have been no changes to the Alere BinaxNOW® Influenza A & B Card 2 test." Therefore, the clinical performance (e.g., sensitivity, specificity) of the assay itself is not being re-evaluated or re-established by this specific submission, but rather the performance of the reader in interpreting those results.

The document discusses analytical performance for the reader with the new software. The acceptance criteria for the analytical studies were generally for the Alere™ Reader with the new software to maintain non-inferiority to the predicate reader (K162642) and to perform reliably in its new "Walk Away" mode.

Acceptance Criteria for Reader Performance (Implicit in comparative studies):

• Accuracy of Interpretation: The modified Reader should accurately interpret positive and negative results from the Alere BinaxNOW® Influenza A & B Card 2, consistently with the predicate device and visual interpretation.
• Timing Accuracy: The "Walk Away" mode should accurately time the 15-minute incubation period.
• Reliability: The Reader should operate reliably without significant errors or invalid results.

Reported Device Performance (from the document, primarily from the Analytical Performance section, not provided here but typically found in a full 510(k) submission):

• Analytical Sensitivity and Specificity: The document implies that the analytical performance (e.g., limit of detection, cross-reactivity) of the test card itself is unchanged, as the card hasn't been modified. The analytical performance of the reader with the new software would be demonstrated by its ability to accurately read a range of low-positive and negative samples consistently.
• Reader Equivalence: The submission aims to demonstrate that the modified Reader is substantially equivalent to the predicate (K162642) through comparative studies, which would show consistent reading of results between the two reader versions.
• "Walk Away" Mode Functionality: The new mode would have been tested to ensure it correctly times and reads the assay at the appropriate interval.

Since comprehensive performance data tables are not in the provided text, a complete table of acceptance criteria and reported numbers cannot be created. The document focuses on declaring substantial equivalence based on the software change.

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

The provided document describes the software modification and its comparison to the predicate device. It states, "The purpose of this Special 510k submission is to bring to market a modification of the software contained on the Alere™ Reader. There have been no changes to the Alere BinaxNOW® Influenza A & B Card 2 test."

This implies that the clinical performance data (sensitivity and specificity for influenza detection) would primarily come from the predicate device's original studies (K162642) or general knowledge of the Alere BinaxNOW® Influenza A & B Card 2 assay's performance.

For the software modification itself, the typical studies would involve:

• Analytical Studies: Testing the new reader's ability to interpret positive and negative control cards, as well as cards with varying antigen concentrations (potentially low-positive). These studies would use a specific number of test cards, but this number is not provided in the excerpt.
• Comparison Studies (Reader vs. Predicate Reader): Testing both the modified reader and the predicate reader on the same set of test cards (potentially clinical samples or spiked samples) to ensure concordance. The sample size for such a comparison is not provided in the excerpt.

Data Provenance: Not explicitly stated for specific test sets related to the software modification. Clinical performance characteristics mentioned (for the assay) were established during the 2015-2016 influenza season.

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

For this type of submission (software modification to an existing reader for an IVD), the "ground truth" for the reader's performance would likely be:

• Reference Method for Assay Results: For clinical performance, a "gold standard" laboratory method like cell culture or an FDA-cleared molecular assay (as mentioned in the Indications for Use) would be used to establish the true presence/absence of influenza in patient samples. This is for the assay's performance, not the reader's.
• Visual Interpretation: For evaluating the reader's accuracy, human visual interpretation by trained personnel (who are considered "experts" in reading the specific lateral flow assay) would often serve as a comparison, or the positive/negative status of contrived samples would be known from spiking.

The document does not provide specific details on the number or qualifications of experts used to establish ground truth for the reader's performance in this particular 510(k) submission.

4. Adjudication Method for the Test Set

The document does not specify any adjudication method for test sets related to the software modification. For analytical studies comparing reader performance, adjudication might involve a third reader or a consensus if discrepancies arise between the reader and a human interpreter. However, this is not explicitly stated.

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. This device is an automated reader for a rapid influenza antigen test. It is not an AI-assisted diagnostic tool designed to improve human reader performance. The Alere™ Reader replaces human visual interpretation of the test card. Its purpose is to provide an objective, automated reading of the results from the immunochromatographic assay. Therefore, an MRMC comparative effectiveness study comparing human readers with and without AI assistance is not applicable to this device.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, implicitly. The Alere™ Reader is a standalone device in the sense that it automatically interprets the test card and reports a result (positive, negative, or invalid) without human interpretation of the test lines. The human interaction is limited to inserting the card and reading the displayed result. The "algorithm" is the reader's software that analyzes the intensity of the test and control lines. The studies supporting this submission would evaluate the performance of this algorithm (software) in correctly reading the test cards.

7. The Type of Ground Truth Used

For the assay's (Alere BinaxNOW® Influenza A & B Card 2) clinical performance (established during the predicate device's evaluation), the indications for use state: "Negative test results are presumptive and should be confirmed by cell culture or an FDA-cleared influenza A and B molecular assay." This indicates that cell culture or an FDA-cleared molecular assay would be considered the ground truth for determining actual influenza infection.

For the reader's performance (the focus of this specific 510(k) for software modification), the ground truth would likely be established by:

• Known concentrations of analyte: For analytical sensitivity.
• Visual interpretation by trained personnel: For concordance studies of the reader against human interpretation of the test card.
• Results from the predicate reader: For demonstrating substantial equivalence of the modified reader.

8. The Sample Size for the Training Set

The document does not provide information about a specific training set. The Alere™ Reader's software likely uses image processing and pattern recognition algorithms that would have been developed and refined using a dataset of test cards (a "training set") to learn to identify and interpret the presence and intensity of test and control lines. However, the size or nature of such a training set is not disclosed in this regulatory summary.

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

As with the training set size, the method for establishing ground truth for any training data used to develop the reader's software is not provided in this document. Typically, for such image-based interpretation systems, ground truth for training data would be established by:

• Manual annotation: Experienced individuals would visually inspect and label images of test cards (e.g., "positive for A," "negative," "invalid").
• Spiked samples with known concentrations: Cards created with precise amounts of antigen to represent known positive or negative results.
• Comparison to a gold standard: For cards from clinical samples, their true status would be confirmed by a reference method (e.g., PCR, cell culture).

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