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The Light Diagnostics Cytomegalovirus Direct Immunofluorescence Assay is intended for use in centrifugation enhanced shell vials in the qualitative detection and identification of immediate early antigen- of human CMV.

Light Diagnostics Cytomegalovirus Direct Immunofluorescence Assay (CMV DFA) uses the standard laboratory direct immunofluorescence technique for the culture confirmation of cytomegalovirus. The DFA is based on the principle of antigen identification using a detector monoclonal antibody conjugated to fluorescein isothiocyanate. The substrate consists of a slide prepared from the tissue cultured cells from a clinical specimen inoculum. Anti CMV FITC laheled antibody is applied to the substrate. The antibody will bind to specific antigen, if present, in the substrate. The fluorescein conjugated monoclonal antibody allows for visualization of the antigen / antibody complex by flucrescence microscopy. Mouse monoclonal antibody is used as the detector antibody in Light Diagnostics Cytomegalovirus Direct Immunofluorescence Assay. The use of monoclonal antibody ensures increased specificity and reduced non-specific interference. The monoclonal antibody is specific for a 68-72 kDa non-structural protein designated as immediate early (IE) antigen of human CMV.

Here's a summary of the acceptance criteria and study details for the Light Diagnostics Cytomegalovirus Direct Immunofluorescence Assay, based on the provided text:

Acceptance Criteria and Device Performance

Study Details

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

   • Sample Size: 516 specimens.
   • Data Provenance: Not explicitly stated, but clinical evaluation was performed. It's likely retrospective given the comparison to existing methods, but this is an inference. No country of origin is mentioned.

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

   • This information is not provided in the summary. The ground truth was established by comparison to "indirect immunofluorescence tests," which are themselves diagnostic methods, not necessarily expert review.

3. Adjudication method for the test set:

   • This information is not provided in the summary. The comparison was made against "indirect immunofluorescence tests."

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:

   • An MRMC study was not performed, nor is AI involved. This is a diagnostic assay, not an AI-assisted interpretation tool.

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

   • Yes, this is a standalone diagnostic assay. Its performance (sensitivity and specificity) was evaluated independently against another diagnostic method.

6. The type of ground truth used:

   • The ground truth was established by comparison to indirect immunofluorescence tests for the detection and identification of CMV. This indicates using a previously established and accepted diagnostic method as the reference standard.

7. The sample size for the training set:

   • This information is not provided. This device is a diagnostic assay, not a machine learning model, so the concept of a "training set" for model development isn't directly applicable in the same way. The development involved characterizing the monoclonal antibody and testing it with reference virus strains and clinical isolates, but a specific "training set size" is not mentioned.

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

   • As mentioned above, the concept of a "training set" for model development isn't directly applicable. For the development/characterization of the assay components, the ground truth was established by:
     • Reacting the anti-CMV antibody with reference virus strains and clinical isolates (implying known CMV status for these samples).
     • Evaluating cross-reactivity with "a variety of viral pathogens and host cell controls" and "a variety of microorganisms" (implying known non-CMV status for these samples).

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