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The Adenovirus Antigen Detection ELISA Test System is an Enzyme-Linked Immunosorbent Assay (ELISA) for the qualitative determination of Adenovirus antigen in human fecal samples as an aid in the diagnosis of acute non-bacterial gastro-enteritis. Performance for this assay has not been established on children over the age of five and immunocompromised patients. The antibody utilized in this assay is a group specific antigen and cannot differentiate between types of adenovirus. Performance of this assay has not been established for specimens other than human feces. For in vitro diagnostic use only.

The Adenovirus Antigen Detection ELISA test is an enzyme linked immunosorbent assay to detect adenovirus antigen in fecal samples. Purified monoclonal antibody specific to adenovirus is attached to a solid phase microtiter well. Diluted fecal sample is added to each well. If the adenovirus antigen is present, it will bind to the monoclonal antibody in the well. After incubation the wells are washed to remove unbound antigen. An enzyme labeled anti-adenovirus polyclonal antibody is added to each well. If antigen is present the conjugate antibody will bind to the antigen attached to the antibody on the well. After incubation the wells are washed to remove unbound conjugate. A substrate solution is added to each well. If enzyme is present the substrate will undergo a color change. After an incubation period the reaction is stopped and the color intensity is measured photometrically, producing an indirect measurement of specific antibody in the patient specimen.

The Trinity Biotech plc. Adenovirus Antigen Detection ELISA Test System underwent several performance studies to establish its effectiveness. The acceptance criteria and reported device performance are summarized below, followed by details of each study.

1. Table of Acceptance Criteria and Reported Device Performance

*Note: Specific numerical acceptance criteria were not explicitly stated in the provided text, so they are inferred based on general expectations for diagnostic device performance. The reported performance values met the implicit high standards for sensitivity, specificity, and agreement compared to predicate methods and for reliability in precision within the context of an ELISA assay.

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

• Study 1 (Relative to Cell Culture):
  • Sample Size: 120 fecal specimens.
  • Data Provenance: Retrospective, frozen fecal specimens sent to a University Virus Reference Laboratory in Ireland for routine testing. 90% of specimens were from adults.
• Study 2 (Relative to Alternate EIA):
  • Sample Size: 481 sera (likely a typo and should be fecal specimens given the device description)
  • Data Provenance: Retrospective, frozen fecal specimens from a large public health lab in the UK. 57% of samples were from patients less than 5 years old and 43% from patients greater than five years old.
• Precision Study:
  • Sample Size: 6 samples (containing Type 2 adenovirus from cell culture), plus positive and negative controls. Each was run in triplicate over three days at three sites, totaling 216 determinations.
  • Data Provenance: Not explicitly stated, but implies laboratory-prepared samples for internal validation.

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

The studies do not mention the use of "experts" in the traditional sense for establishing ground truth, such as radiologists or pathologists making diagnoses. Instead, the ground truth was established by established laboratory methods:

• Study 1: Ground truth was established by cell culture isolation, with positive cultures confirmed by electron microscopy (EM) using a standard negative staining technique (considered presumptive for adenovirus types 40 and 41).
• Study 2: Ground truth was primarily established by a commercially available alternate adenovirus EIA. For discordant samples, Electron Microscopy (EM) was used for confirmation.

No specific number or qualifications of "experts" (e.g., a board-certified virologist with X years of experience) were provided for interpreting these laboratory results; it is assumed that these benchmark methods were performed by qualified laboratory personnel following standard procedures.

4. Adjudication Method for the Test Set

• Study 1: No specific adjudication method was described beyond the initial cell culture and EM confirmation. "Equivocals" (2 samples) were excluded from the final calculations but not explicitly adjudicated further.
• Study 2: For samples where the device ELISA and the alternate EIA produced discordant results, these discrepant samples were re-tested, and any remaining discordant samples (15 in total) were then tested by Electron Microscopy (EM) for resolution. This implies a form of sequential adjudication.

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 ELISA test, not an AI-assisted diagnostic tool that involves human readers interpreting images or data alongside an AI.

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

• Yes, the performance characteristics described (Sensitivity, Specificity, Limit of Detection, Precision, Cross-Reactivity) represent the standalone performance of the ELISA test system itself, without human-in-the-loop performance considerations beyond standard laboratory procedures for running the assay and interpreting the quantitative optical density readings against a cut-off.

7. The Type of Ground Truth Used

• Study 1: The ground truth was based on a predicate laboratory method (cell culture isolation), confirmed by electron microscopy (EM). This is a form of laboratory gold standard for detecting the presence of adenovirus.
• Study 2: The primary comparison was against an alternate commercially available adenovirus EIA. For discordant results, electron microscopy (EM) served as the confirmatory ground truth.

8. The Sample Size for the Training Set

No explicit "training set" is mentioned in the context of machine learning. For an ELISA test, the development process involves identifying antibodies and optimizing assay parameters. The performance studies detailed are validation studies for the finalized assay.

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

As this is an ELISA diagnostic kit and not an AI/machine learning device, the concept of a "training set" and establishing ground truth for it in the AI context does not directly apply. The development of the antibody and assay would have relied on known positive and negative controls and characterized samples to establish appropriate binding and detection parameters, but these are not referred to as a "training set" in the document.

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