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The Diagnostic Hybrids, Inc. device, D3 FastPoint L-DFA Parainfluenza Virus/Adenovirus Identification Kit is intended for the qualitative identification of adenovirus and to screen for the presence of parainfluenza virus types 1, 2, and 3 in nasal and nasopharyngeal swabs and aspirates/washes specimens from patients with signs and symptoms of respiratory infection by direct detection of immunofluorescence using monoclonal antibodies (MAbs).

It is recommended that specimens found to be negative for parainfluenza virus and adenovirus after examination of the direct specimen result be confirmed by cell culture. Negative results do not preclude parainfluenza virus and adenovirus infection and should not be used as the sole basis for diagnosis, treatment or other management decisions.

The D3 FastPoint L-DFA Parainfluenza Virus/Adenovirus Identification Kit (D3 FastPoint PIV/ADV Kit) uses a blend (called an "L-DFA Reagent") of viral antigen-specific murine monoclonal antibodies that are directly labeled with either R-phycoerythin (PE) (parainfluenza virus types 1, 2 and 3) or fluorescein isothiocyanate (FITC) (adenovirus) for the qualitative identification of adenovirus and to screen for the presence of parainfluenza virus types 1, 2, and 3.

The cells to be tested are derived from respiratory specimens from patients with signs and symptoms of respiratory infection. The cells are permeabilized and stained concurrently in a liquid suspension format with the L-DFA Reagent. After incubating at 35℃ to 37℃ for 5-minutes, the stained cell suspensions are rinsed with 1X PBS. The rinsed cells are pelleted by centrifugation and then re-suspended with the Resuspension Buffer and loaded onto a specimen slide well. The cells are examined using a fluorescence microscope. Cells infected with parainfluenza virus types 1, 2 and 3 will exhibit golden-yellow fluorescence. Cells infected with adenovirus will exhibit apple green fluorescence due to the FITC. Non-infected cells will exhibit red fluorescence due to the Evans Blue counter-stain. Nuclei of intact cells will exhibit orange-red fluorescence due to the propidium iodide.

Here's an analysis of the provided document regarding the acceptance criteria and study for the D3 FastPoint L-DFA Parainfluenza Virus/Adenovirus Identification Kit:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" in a numerical target format (e.g., "sensitivity must be >90%"). Instead, it presents the achieved performance metrics in comparison to a composite comparator method (FDA-cleared device + viral culture). For the purpose of this table, I'll extract the reported performance from the clinical study, which implicitly serves as the demonstration of meeting acceptable clinical performance for substantial equivalence.

Acceptance Criteria (Implied by Study Results & Predicate Equivalence) and Reported Device Performance

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

• Test Set (Clinical Performance Study):

  • Total Specimen Sample Size: 1519 specimens (across all age groups and specimen types).
  • NP Wash/Aspirate (Combined Sites 1, 2, 3):
    • Parainfluenza Virus: 628 specimens
    • Adenovirus: 632 specimens
  • NP Swab (Combined Sites 3, 4):
    • Parainfluenza Virus: 682 specimens
    • Adenovirus: 681 specimens
  • Data Provenance: Prospective, collected from 4 geographically diverse U.S. clinical laboratories during the 2009 respiratory virus season (January-March 2009). The specimens were "excess, remnants of respiratory specimens that were prospectively collected from symptomatic individuals suspected of respiratory infection" and were de-identified.

• Test Set (Reproducibility Study):

  • Sample Size: A reproducibility panel consisting of 5 randomized panel members, tested daily in two separate runs for 5 days by four different laboratories (40 total runs). Each panel member contained defined levels of infected or non-infected cells.
  • Data Provenance: Not specified beyond being conducted by "four different laboratories." This would be part of a controlled laboratory study, not clinical specimens.

3. Number of Experts and Qualifications for Ground Truth (Clinical Test Set):

• The document does not explicitly state the number of experts (e.g., medical doctors, virologists) used to establish the ground truth for the clinical test set.
• Qualifications of Experts (Implied): The ground truth was established using a "composite comparator method" which included:
  • Direct Specimen Fluorescent Antibody (DSFA) test with an FDA-cleared device. This implies that the interpretation of the comparator DSFA test would have been performed by qualified laboratory personnel trained in using that specific FDA-cleared device.
  • Viral culture confirmation. This would have been performed by trained microbiologists or virologists capable of performing and interpreting viral cultures.

4. Adjudication Method for the Test Set (Clinical Study):

• Adjudication Method: The ground truth was established using a composite comparator method.
  • "True" positive was defined as any sample that either tested positive by the comparator DSFA test or viral culture.
  • "True" negative was defined as any sample that tested negative by both the comparator DSFA test and viral culture.
  • This is a form of adjudicated reference standard, where agreement between multiple methods (or sequential application of methods, as implied by "negatives followed by culture") establishes the "truth." This method is commonly used when a single perfect gold standard is not available or practical.

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

• No, an MRMC comparative effectiveness study was not explicitly described. The study focused on the standalone performance of the D3 FastPoint kit against a composite comparator. There is no mention of human readers using the D3 FastPoint kit with and without AI assistance (as would be the case for a typical MRMC study involving AI) nor an effect size for human reader improvement with AI.

6. Standalone (Algorithm Only) Performance Study:

• Yes, a standalone study was performed. The clinical performance section directly assesses the D3 FastPoint L-DFA Parainfluenza Virus/Adenovirus Identification Kit's performance (device only, without human-in-the-loop assistance beyond the interpretation of the kit's results) against a composite comparator method. The sensitivity and specificity values reported in Tables 5.6, 5.7, 5.8, and 5.9 represent this standalone performance.

7. Type of Ground Truth Used (Clinical Study):

• Composite Comparator Method: The ground truth for the clinical study was established using a composite comparator method. This method combined:
  • Performance of an existing FDA-cleared DSFA device.
  • Viral culture confirmation for all specimens negative by the initial comparator DSFA.
  • This combines elements of an established diagnostic method (FDA-cleared device) with a traditional gold standard for viral identification (viral culture).

8. Sample Size for the Training Set:

• The document does not report on a training set sample size. This is because the device described is a diagnostic kit (reagents and controls for immunofluorescence), not an AI/machine learning algorithm that typically requires a distinct training phase. Performance is evaluated through analytical and clinical studies, not by training a model.

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

• Not applicable, as there is no training set described for an AI/machine learning model. The kit itself is the "algorithm" in a sense, and its performance is validated through analytical studies (reproducibility, LOD, inclusivity) and clinical studies against established comparator methods.

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