Search Results

The BinaxNOW® Influenza A & B Test is an in vitro immunochromatographic assay for the qualitative detection of influenza A and B nucleoprotein antigens in nasopharyngeal (NP) swab, nasal swab, and nasal wash/aspirate specimens. It is intended to aid in the rapid differential diagnosis of influenza A and B viral infections. Negative results do not preclude influenza virus infection and should not be used as the sole basis for treatment or other management decision.

The BinaxNOW® Influenza A & B Test is an immunochromatographic membrane assay that uses highly sensitive monoclonal antibodies to detect influenza type A & B nucleoprotein antigens in respiratory specimens. These 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. This test strip is mounted inside a cardboard, book-shaped hinged test device. Swab specimens require a sample preparation step, in which the sample is eluted off the swab into elution solution, saline, or transport media. Nasal wash/aspirate samples require no preparation. Sample is added to the top of the test strip and the test device is closed. Test results are interpreted at 15 minutes based on the presence or absence of pink-to-purple colored Sample Lines. The blue Control Line turns pink in a valid assay.

Here's a breakdown of the acceptance criteria and study details for the BinaxNOW® Influenza A & B Test, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for sensitivity and specificity are not explicitly stated as pre-defined targets within the provided text. Instead, the document presents the observed performance of the device against the reference method (cell culture/DFA) in various clinical studies. The substantial equivalence is established by comparing this observed performance to the predicate device, the BD Directigen™ Flu A+B Test (though detailed performance for the predicate is not provided in this summary).

For the purpose of this analysis, we will present the reported device performance from the prospective and retrospective clinical studies.

BinaxNOW® Influenza A & B Test Performance vs. Cell Culture/DFA (Prospective Study)

BinaxNOW® Influenza A & B Test Performance vs. Cell Culture/DFA (Retrospective Study)

Analytical Sensitivity (Limit of Detection - LOD)

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

• Prospective Study Test Set:
  • Total Specimens: 846
  • Provenance: Multi-center, "central testing laboratory outside the US during the 2004 respiratory season and at three US trial sites during the 2005-2006 respiratory season." Data is prospective.
  • Patient demographics: 44% male, 54% female, 54% pediatric (

Ask a specific question about this device

The BinaxNOW® Influenza A & B Test is an in vitro immunochromatographic assay for the qualitative detection of influenza A and B nucleoprotein antigens in nasopharyngeal swab and nasal wash/aspirate specimens. It is intended to aid in the rapid differential diagnosis of influenza A and B viral infections. Negative test results should be confirmed by culture.

The BinaxNOW® Influenza A & B Test is an immunochromatographic membrane assay that uses highly sensitive monoclonal antibodies to detect influenza type A & B nucleoprotein antigens in nasopharyngeal specimens. These 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. This test strip is mounted inside a cardboard, bookshaped hinged test device.

Swab specimens require a sample preparation step, in which the sample is eluted off the swab into elution solution or transport media. Nasal wash/aspirate samples require no preparation. Sample is added to the top of the test strip and the test device is closed. Test results are interpreted at 15 minutes based on the presence of pink-to-purple colored Sample Lines. The blue Control Line turns pink in a valid assay.

Here's an analysis of the provided text regarding the BinaxNOW® Influenza A & B Test, focusing on acceptance criteria, study details, and data provenance:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the BinaxNOW® Influenza A & B Test are implicitly derived from its comparison to a clinical reference method (cell culture/DFA) and to its predicate devices (Binax NOW® Flu A Test and Binax NOW® Flu B Test). The study aimed to demonstrate acceptable sensitivity and specificity.

Note: The document does not explicitly state numerical acceptance criteria in the typical "must achieve X% sensitivity and Y% specificity" format. Instead, the performance is presented to demonstrate substantial equivalence to established methods and predicate devices. The clinical study against culture/DFA has very small numbers of positive cases, leading to wide confidence intervals and potentially lower apparent sensitivity. The studies against the predicate Binax NOW® Flu A and B tests show much stronger performance, suggesting the extended claim focuses on maintaining equivalence to those previously cleared devices.

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

• Clinical Study (BinaxNOW® Influenza A & B Test Performance vs. Cell Culture / DFA):
  • Sample Size: 114 specimens (113 NP swab, 1 wash/aspirate).
  • Data Provenance: Prospective study conducted in 2004 outside the US. Specimens collected from children (=18 years) presenting with influenza-like symptoms.
• Clinical Study (BinaxNOW® Influenza A & B Test Performance vs. Binax NOW® Flu A and Flu B Tests):
  • Sample Size: 306 retrospective frozen clinical samples for Flu A comparison; 303 retrospective frozen clinical samples for Flu B comparison.
  • Data Provenance: Retrospective frozen clinical samples. Collected from symptomatic patients at multiple physician offices, clinics, and hospitals in the Southern, Northeastern, and Midwestern regions of the United States, and one hospital in Sweden.
• Clinical Study (Binax NOW® Flu A and Flu B Test Performance vs. Cell Culture - for predicate devices):
  • Sample Size: 373 prospective clinical samples.
  • Data Provenance: Multi-center prospective study conducted during the 2002 Flu season at physician offices and clinics in the Western and mid-Atlantic United States.

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

The document does not specify the number or qualifications of experts used to establish the ground truth.

• For the prospective study comparing the BinaxNOW® combined test to cell culture/DFA, "cell culture and/or DFA" serves as the reference standard (ground truth). It is assumed these reference methods were performed by qualified laboratory personnel, but no specifics are given.
• For the retrospective study comparing the BinaxNOW® combined test to the individual NOW® Flu A and Flu B Tests, those individual tests are treated as the reference standard.
• For the predicate device studies, "cell culture" served as the reference.

4. Adjudication Method for the Test Set

The document does not specify an adjudication method for the test set. It mentions that "Test results are interpreted at 15 minutes based on the presence of pink-to-purple colored Sample Lines. The blue Control Line turns pink in a valid assay." This suggests a single interpretation per device, without multi-reader adjudication outlined. For the analytical sensitivity, 12 different operators interpreted devices to determine the LOD.

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

No MRMC comparative effectiveness study was done. This device is an in vitro diagnostic (IVD) rapid immunoassay, not an AI-assisted diagnostic tool for interpretation by human readers. The output is a visual presence or absence of a line on a test strip.

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

Yes, the performance data presented are for the device (the BinaxNOW® Influenza A & B Test) as a standalone diagnostic tool. It is a rapid immunoassay that outputs a visual result, which is then interpreted by a human, but the performance metrics provided (sensitivity, specificity) reflect the device's ability to detect the antigen itself, not the human interpreter's performance. The analytical studies (analytical sensitivity, reactivity testing, analytical specificity) are also standalone performance evaluations of the device.

7. The Type of Ground Truth Used

• Clinical Study (BinaxNOW® Influenza A & B Test Performance vs. Cell Culture / DFA): Cell Culture and/or Direct Fluorescent Antibody (DFA). This is a laboratory-based reference standard.
• Clinical Study (BinaxNOW® Influenza A & B Test Performance vs. Binax NOW® Flu A and Flu B Tests): The individual Binax NOW® Flu A and Flu B Tests (predicate devices) were used as the reference standard.
• Clinical Study (Binax NOW® Flu A and Flu B Test Performance vs. Cell Culture - for predicate devices): Cell Culture.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of device development (e.g., machine learning training). As a rapid immunoassay, this device relies on biological interactions (antibody-antigen binding) rather than a trained algorithm. The various analytical and clinical studies serve to validate its performance.

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

Not applicable, as there is no mention of a "training set" in the machine learning sense for this immunochromatographic device. The development and optimization of such assays would involve extensive in-house testing using characterized positive and negative samples, but these are not typically referred to as a "training set" in the regulatory context for IVDs.

Ask a specific question about this device