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The ViraSTAT® FITC-Labeled Anti-Influenza test panel is intended for the qualitative detection and confirmation of influenza A and B virus isolates from infected cell cultures through the use of the ViraSTAT® FITC-Labeled Anti-Influenza Pool and the identification and confirmation of influenza A and B by typing with separate ViraSTAT® FITC-Labeled Anti-Influenza type A or B, monoclonal antibodies, respectively. Performance characteristics have not been established for direct specimen staining.

The ViraSTAT® FITC-Labeled Anti-Influenza A and B monoclonal antibodies are fluorescently-labeled antibodies for use in culture confirmation of influenza A and B infections, respectively, in standard cell culture. The virus to be detected is grown in the appropriate cell culture system, fixed on a slide or coverslip and then the cell preparation is stained with the fluorescently-labeled monoclonal antibody. The stained sample is then viewed under a fluorescent microscope for a positive or negative identification. A positive sample is determined when cells displaying typical apple-green fluorescence are observed. Fluorescence may be present in the nucleus alone, in the nucleus and the cytoplasm, or in the cytoplasm alone. A negative sample is determined when slide wells or coverslips show no specific apple-green fluorescence in the cells and have at least 50 intact red counterstaining cells per well or 50% of the monolayer remaining on the coverslips or slides that are counterstained red.

Here's a breakdown of the acceptance criteria and study details for the ViraSTAT® FITC-Labeled Anti-Influenza A and B Monoclonal Antibodies:

1. Acceptance Criteria and Reported Device Performance

The documentation doesn't explicitly state quantitative acceptance criteria (e.g., "Sensitivity must be > 95%"). Instead, it states the performance of the ViraSTAT® device should be "equivalent to" the predicate devices. The reported performance details indicate that this equivalence was achieved:

Interpretation: The ViraSTAT® device demonstrated 100% agreement with the reference monoclonal antibodies for both positive and negative influenza A and B samples, and showed no cross-reactivity, thus meeting the implicit acceptance criterion of "equivalence."

2. Sample Size and Data Provenance

• Test Set Sample Size: 962 culture isolates.
  • 363 identified as influenza A
  • 99 identified as influenza B
  • 500 identified as influenza-negative
• Data Provenance: The majority (944) were culture isolates from fresh throat swab specimens. The rest were from frozen isolates. No country of origin is specified, but the submission is to the FDA in the USA. The study appears to be retrospective, using collected culture isolates. Four test sites were involved.

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 for the test set. The ground truth was established by "commercially available 510(k) marketing-cleared monoclonal antibodies" from Bartels' Viral Respiratory Screening and Identification Kit and Dako's Imagen Influenza A and B Kit. It is implied that these reference methods were interpreted by trained laboratory personnel.

4. Adjudication Method

The document does not describe an adjudication method for the test set. The performance was directly compared against the results from the predicate (reference) antibodies.

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

No MRMC comparative effectiveness study was done. This study focuses on the standalone performance of the diagnostic antibodies against established reference antibodies, not on reader performance with or without AI assistance.

6. Standalone (Algorithm Only) Performance

Yes, a standalone study was performed. The "device" in this context refers to the antibody reagents. The performance data presented (sensitivity and specificity) are a direct comparison of how well the ViraSTAT® antibodies perform on culture isolates compared to the reference antibodies, without human-in-the-loop assistance influencing the antibody reaction. Human interpretation of the stained cells under a fluorescent microscope is still required, but the performance of the reagent itself is what's being evaluated as standalone.

7. Type of Ground Truth Used

The ground truth used was established by reference methods/predicate devices, specifically "commercially available 510(k) marketing-cleared monoclonal antibodies" (Bartels' Viral Respiratory Screening and Identification Kit and Dako's Imagen Influenza A and B Kit) used on cell culture isolates. This could be considered a form of expert consensus or established laboratory standard as these predicate devices themselves would have undergone validation.

8. Sample Size for Training Set

The document does not mention a separate "training set" or its sample size. This type of device (monoclonal antibodies) typically doesn't involve machine learning models that require training sets in the same way modern AI algorithms do. The "development" of the antibodies would involve laboratory work to select and validate clones, but this is distinct from how an AI training set is generally discussed. The 962 culture isolates would be considered the clinical performance validation set.

9. How Ground Truth for Training Set Was Established

As there is no explicit training set in the context of AI/machine learning, this question is not directly applicable. The "ground truth" for the development of the antibodies (e.g., confirming their binding specificity) would have been established through standard immunological and virological laboratory techniques using known influenza A and B strains and other non-influenza viruses.

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The ZstatFlu® Test for Influenza Type A and B Viruses is an endogenous viral-encoded enzyme assay (EVEA) and is intended for use in the qualitative determination of influenza types A and B from throat swab specimens. The ZstatFlu® Test for Influenza Type A and B Viruses is not intended for the detection of influenza C. This test is indicated for the direct testing of patients presenting with influenza-like illnesses.

The Improved ZstatFlu® Test for Influenza Types A and B Virus is an endogenous viralencoded enzyme assay (EVEA) and is intended for use in the qualitative determination of influenza types A and B from throat swab specimens. The Improved ZstatFlu® Test for Influenza Types A and B Virus is not intended for the detection of influenza C. Influenza types A and B virus possess surface glycoproteins with neuraminidase activity, that hydrolyze substrates which contain alpha-ketosidically linked N-acetyIneuraminic acid (Neu5Ac). A modified Neu5Ac molecule has been synthesized and coupled to a chromogen to produce the neuraminidase substrate. In the presence of influenza types A and B virus the chromogenic substrate is then cleaved by the action of viral neuraminidase, releasing a free chromogen. This free chromogen precipitates to produce a blue color. The blue precipitate is then concentrated and collected from the reaction mixture onto a filter device.

Here's a breakdown of the acceptance criteria and study details for the ZstatFlu® Test for Influenza Types A and B Virus, based on the provided document:

Acceptance Criteria and Device Performance

The document does not explicitly state pre-defined "acceptance criteria" with numerical thresholds for sensitivity and specificity that the device was required to meet. Instead, it reports the observed performance characteristics from the clinical study. The FDA's letter of clearance (K982429) confirms that the device was found substantially equivalent to legally marketed predicate devices, implying that its performance was deemed acceptable for its intended use.

Here are the reported performance characteristics:

Study Details

1. Sample Size used for the test set and the data provenance:

   • Sample Size: 157 throat swab specimens.
   • Data Provenance:
     • Country of Origin: United States.
     • Retrospective or Prospective: The specimens were collected from field sites during the 1995-96 influenza season (November 11, 1995 to March 29, 1996) and then tested. This indicates a prospective collection for the purpose of the study.
     • Collection Sites: Seven separate locations throughout the United States, including physician offices, laboratories, clinics, and hospital settings. Specifically, six physicians and their nurses and technicians from two physician offices in a Southwest region participated in collection and testing.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

   • The document does not explicitly state the number of individual experts or their specific qualifications (e.g., radiologist with X years of experience).
   • However, it mentions "the reference method of viral isolation and culture confirmation with monoclonal antibodies" conducted at a "Southwestern viral testing laboratory." This implies that trained laboratory personnel and virologists were involved in establishing the ground truth, but specific numbers and detailed qualifications are not provided.

3. Adjudication method for the test set:

   • The document does not mention an adjudication method (like 2+1 or 3+1) for the interpretation of the reference method results. It simply states the reference method was "viral isolation and culture confirmation with monoclonal antibodies."

4. 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, a multi-reader multi-case (MRMC) comparative effectiveness study was not conducted. This is an in vitro diagnostic device (IVD) for direct detection of viruses, and the study design focuses on comparing the device's performance against a laboratory reference standard, not human reader performance.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

   • Yes, the performance data presented is for the device in a standalone manner (algorithm only, without human-in-the-loop performance in terms of interpretation, other than operating the test according to instructions). The test is an "endogenous viral-encoded enzyme assay (EVEA)" that produces a visible color change, which is then presumably read and interpreted by the user of the device. The reproducibility studies, however, did assess variations across different users and settings.

6. The type of ground truth used:

   • The ground truth used was laboratory reference standard: viral isolation and culture confirmation with monoclonal antibodies.

7. The sample size for the training set:

   • The document does not specify a separate training set or its sample size. The ZstatFlu® test is described as an "endogenous viral-encoded enzyme assay (EVEA)" based on a chemical reaction, not a machine learning algorithm that typically requires a training set. Manufacturers of such diagnostic kits typically validate the assay's performance characteristics through analytical and clinical studies, rather than "training" an AI model.

8. How the ground truth for the training set was established:

   • Not applicable, as there is no mention of a traditional "training set" for a machine learning model.

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The ViraZyme® Influenza ID test is a direct specimen test indicated for use in the qualitative detection of both influenza types A and B virus from throat swab specimens. The ViraZyme® Influenza ID test may be used when a patient is suspected of having symptoms of an influenza-like illness. These symptoms can include, but are not limited to the following: fever of 38.5℃, sore throat, headache, myalgia, rhinitis, vomiting, chills, malaise, and cough. A positive ViraZyme® result would indicate the presence of influenza type A or B virus. A negative result is considered presumptive and should be confirmed by culture. The ViraZyme® Influenza ID test does not detect influenza C, and is indicated for in Vitro Diagnostic Use only.

The ViraZyme® Influenza ID Test for Influenza Types A and B Viruses is an endogenous viralencoded enzyme assay (EVEA) and is intended for use in the qualitative determination of influenza types A and B from throat swab specimens. The ViraZyme® Influenza ID Test is not intended for the detection of influenza C.

Influenza types A and B virus possess surface glycoproteins with neuraminidase activity, that hydrolyze substrates which contain alpha-ketosidically linked N-acetylneuraminic acid (Neu5Ac). A modified Neu5Ac molecule has been synthesized and coupled to a chromogen to produce the neuraminidase substrate. In the presence of influenza types A and B virus the chromogenic substrate is then cleaved by the action of viral neuraminidase, releasing a free chromogen. This free chromogen precipitates to produce a blue color. The blue precipitate is then concentrated and collected from the reaction mixture onto a filter device.

ViraZyme® Influenza ID Test: Acceptance Criteria and Performance

1. Acceptance Criteria and Reported Device Performance

The provided document does not explicitly state pre-defined acceptance criteria. However, it presents the clinical performance of the ViraZyme® Influenza ID Test against a reference method. Based on the reported results, we can infer the achieved performance metrics.

Note: The inferred "Acceptance Criteria" are based on the typical expectations for in vitro diagnostic tests used as screening tools, where high specificity is often prioritized to minimize false positives, and sensitivity is acceptable for a screening test that would be confirmed by a more definitive method. The 100% reproducibility is explicitly stated as demonstrating adequate performance across different environments.

2. Sample Size for the Test Set and Data Provenance

• Sample Size for Test Set: 157 throat swab specimens.
• Data Provenance: The data was collected from field sites across the United States during the 1995-96 influenza season (November 11, 1995 to March 29, 1996). This was a prospective study, as specimens were collected specifically for this evaluation.

3. Number of Experts Used to Establish Ground Truth and Qualifications

The document does not explicitly state the number of experts or their specific qualifications (e.g., number of years of experience). However, it mentions that the reference method involved "viral isolation and culture confirmation with monoclonal antibodies" which is a laboratory-based gold standard. This process would typically be performed and interpreted by trained laboratory personnel, likely microbiologists or virologists, with expertise in viral culture and identification.

4. Adjudication Method

The document does not describe an explicit adjudication method (e.g., 2+1, 3+1). The ground truth was established by a single reference method: viral isolation and culture confirmation with monoclonal antibodies. There is no indication of multiple expert readings or a consensus process for the reference method.

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

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. The study focuses solely on the standalone performance of the ViraZyme® Influenza ID Test compared to a laboratory reference method. There is no mention of human readers' performance with or without AI assistance, as this is an in-vitro diagnostic test, not an AI-assisted diagnostic tool for human interpretation.

6. Standalone Performance

Yes, a standalone performance study was done. The entire clinical evaluation described in the document assesses the ViraZyme® Influenza ID Test's performance (algorithm/assay only, without human-in-the-loop interpretation impacting the result) against the reference method. The reported sensitivity and specificity values are for the device's standalone performance.

7. Type of Ground Truth Used

The type of ground truth used was viral isolation and culture confirmation with monoclonal antibodies. This is considered a highly reliable and definitive method for identifying influenza viruses.

8. Sample Size for the Training Set

The document does not provide any information regarding a distinct training set sample size. The clinical study described in the document appears to be solely for validation/testing purposes. It's possible that the device's development involved internal studies or smaller pilot data not mentioned in this summary, but no details are provided.

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

As no information regarding a separate training set is provided, there is no information on how its ground truth would have been established.

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The ViraZyme® Culture Confirmation Screen for Influenza and Parainfluenza is intended for use as a screening test for respiratory viral cultures infected with influenza type A and B and parainfluenza types 1, 2, 3, and 4. This test will screen culture fluids for the presence of these viruses, but it is not indented for the definitive typing of these viruses.

Influenza and parainfluenza viruses posses surface glycoproteins with neuraminidase activity, that hydrolyze substrates which contain alphaketosidically linked N-acetylneuraminic acid (Neu5Ac). A modified Neu5Ac molecule has been synthesized and coupled to a chromogen to produce the neuraminidase substrate. In the presence of influenza and parainfluenza the chromogenic substrate is then cleaved by the action of viral neuraminidase, releasing a free chromogen. This free chromogen is then precipitated by combining with a diazonium salt to produce a red color. The red precipitate is then concentrated and collected from the solution onto a filter device.

Here's the analysis of the provided text regarding the acceptance criteria and study for the ViraZyme® Culture Confirmation Screen:

Note: The provided document is a 510(k) summary for a diagnostic test, not an AI/ML device. Therefore, several sections of your request (e.g., MRMC studies, AI improvement, training set details) are not applicable and will be marked as such.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria in terms of a specific sensitivity or specificity threshold. Instead, it presents the "Performance Characteristics" from several studies as the evidence of effectiveness. The general acceptance criterion implied is that the device demonstrates a high degree of agreement with standard culture confirmation methods using monoclonal antibodies (IFA).

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

The studies involved a total of 800 specimens across four locations.

• Southern medical center: 177 previously identified patient specimens (retrospective, from freeze). Data from the United States.
• Southwestern medical center: 97 previously identified patient specimens (retrospective, from freeze). Data from the United States.
• Midwestern medical center: 123 previously identified patient specimens (retrospective, from freeze). Data from the United States.
• In-house evaluation (Southwest): 403 previously identified frozen and fresh patient specimens (mix of retrospective and prospective). Data from the United States.

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

The ground truth was established by "standard culture confirmation with monoclonal antibodies (IFA)." This refers to laboratory testing, not human expert interpretation in the way one might consider a radiologist or pathologist. Therefore, the concept of "number of experts" or their specific qualifications for establishing ground truth as interpreted here (e.g., radiologist with X years of experience) is not applicable. The implicit "experts" are the trained medical technologists performing the standard IFA diagnostic tests.

4. Adjudication Method for the Test Set

Not applicable. The ground truth was established by a standard laboratory technique (IFA), not through a subjective interpretation that would require an adjudication method like 2+1 or 3+1.

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

Not applicable. This is a diagnostic test kit, not an AI/ML device involving human readers or AI assistance.

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

This refers to the performance of the ViraZyme® assay itself (the "device") independently. The studies presented are standalone performance evaluations of the ViraZyme® assay compared to the IFA (Immunofluorescence Assay) gold standard. The device operates automatically by detecting the enzymatic reaction; there is no human-in-the-loop performance component beyond sample preparation and reading the color change.

7. The Type of Ground Truth Used

The ground truth used was "standard culture confirmation with monoclonal antibodies (IFA)". This is a well-established laboratory diagnostic method for viral identification and is considered the reference standard in this context.

8. The Sample Size for the Training Set

Not applicable. This is a chemical/enzymatic diagnostic assay, not an AI/ML algorithm that requires a "training set."

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

Not applicable, as there is no training set for this type of device.

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