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The Alere™ Influenza A & B Test is an in vitro immunochromatographic assay for the qualitative detection of influenza A and B nucleoprotein antigens in nasal swab specimens collected from symptomatic patients. 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.

The Alere™ Influenza A & B Test is an immunochromatographic membrane assay that uses highly sensitive monoclonal antibodies to detect influenza type A and B nucleoprotein antigens in nasal swab specimens. These antibodies and a control protein are immobilized onto a membrane support as three distinct lines and are combined with other reagents/pads to construct a Test Strip.

Nasal swab samples are added to a Coated Reaction Tube to which an extraction reagent has been added. An Alere™ Influenza A & B Test Strip is then placed in the Coated Reaction Tube holding the extracted liquid sample. Test results are interpreted at 10 minutes based on the presence of pink-to-purple colored Sample Lines. The yellow Control Line turns blue in a valid test.

Here's an analysis of the provided text, outlining the acceptance criteria and study details for the Alere™ Influenza A & B Test:

The Alere™ Influenza A & B Test is an in vitro immunochromatographic assay for the qualitative detection of influenza A and B nucleoprotein antigens in nasal swab specimens. It's intended to aid in the rapid differential diagnosis of influenza A and B viral infections.

Acceptance Criteria and Device Performance

The provided document details the performance of the Alere™ Influenza A & B Test against viral culture as the ground truth. While explicit "acceptance criteria" are not stated as target thresholds in this document, the reported performance metrics are presented against the comparison method. We can infer the implied acceptance would be that the device demonstrates adequate diagnostic accuracy (sensitivity and specificity) to be useful for its intended purpose.

Here's the performance as reported in the clinical study:

Study Details

2. Sample Size and Data Provenance

• Test Set Sample Size: A total of 470 prospective nasal swab specimens were evaluated.
• Data Provenance:
  • Country of Origin: The study was conducted at seven U.S. trial sites.
  • Retrospective/Prospective: The study was a "multi-center, prospective, clinical study conducted at seven U.S. trial sites during the 2008-2009 respiratory season."

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the number or specific qualifications of experts used to establish the ground truth (viral culture). Viral culture itself is a laboratory gold standard, and its interpretation would typically be performed by trained laboratory personnel or microbiologists.

4. Adjudication Method for the Test Set

The document does not describe a formal adjudication method (e.g., 2+1, 3+1) for discordant results between the Alere™ Influenza A & B Test and viral culture for the primary clinical study. However, for the 19 samples where the Alere™ test was negative but culture was positive for influenza B, an investigational RT-PCR assay was used. "Ten (10) of these samples were negative for influenza B by PCR," suggesting a form of secondary confirmation for these specific discrepancies.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

There is no indication that a multi-reader multi-case (MRMC) comparative effectiveness study was done to assess how much human readers improve with AI vs. without AI assistance. This device is a rapid diagnostic test (immunochromatographic assay), not an AI-assisted diagnostic tool for image interpretation or complex data analysis that would typically involve human readers interpreting results.

6. Standalone Performance

Yes, the clinical study directly assesses the standalone performance (algorithm only, without human-in-the-loop performance) of the Alere™ Influenza A & B Test. The reported sensitivity, specificity, and invalid rate are for the device itself against the viral culture.

7. Type of Ground Truth Used

The primary ground truth used for the clinical study was viral culture.
For discordant Influenza B results (Alere negative, culture positive), an investigational RT-PCR assay was used as a secondary confirmation method.

8. Sample Size for the Training Set

The document does not specify a separate "training set" sample size in the context of device development for this immunochromatographic assay. Such devices are typically developed through analytical studies and optimization of reagents, rather than machine learning models that require distinct training sets. The "Analytical Sensitivity" section involved testing various concentrations of influenza viruses, which could be considered part of the development and optimization process, but not a typical "training set" in the AI sense.

9. How Ground Truth for the Training Set Was Established

As there is no explicit "training set" in the context of a machine learning algorithm, the concept of establishing ground truth for a training set does not directly apply here. The analytical studies (Analytical Sensitivity, Analytical Reactivity, Analytical Specificity) used well-characterized viral strains and microorganisms, where their presence and concentration served as the known "ground truth" for evaluating the immunoassay's performance characteristics. This would involve laboratory-established concentrations and identification of these biological agents.

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