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The Diagnostic Hybrids, Inc. device, D3 DFA Cytomegalovirus Immediate Early Antigen Identification Kit, is intended for use in the qualitative detection and identification of human Cytomegalovirus (CMV) immediate early antigen (IEA) in cell cultures by immunofluorescence using fluoresceinated monoclonal antibodies (MAbs).

This product is not intended for use in testing blood or plasma donors and is not intended for use in direct detection of cytomegalovirus in clinical specimens.

Two murine derived monoclonal antibodies (MAbs) are used in the Diagnostic Hybrids, Inc. (DHI) device, D3 DFA Cytomegalovirus Immediate Early Antigen Identification Kit (CMV-IEA ID Kit), and are directed against CMV immediate early antigen (pp 72). The MAbs used in the Kit have been shown to be highly specific, with no cross-reactivity to other cultured viruses. The MAbs have been labeled by DHI using Fluorescein Isothiocyanate (FITC).

Kit Components:

1. CMV-IEA DFA Reagent, 10-mL. One dropper bottle containing a mixture of two murine MAbs directed against CMV immediate early antigen (pp 72). The MAbs are both IgG1 (k) isotype. The buffered, stabilized, aqueous solution contains Evans Blue as a counter-stain and 0.1% sodium azide as preservative.
2. CMV Antigen Control Slides, 5-slides. Individually packaged control slides containing wells with cell culture derived positive and negative control cells. Each slide contains one Negative well of uninfected cells and one Positive well of CMV infected cells. Each slide is intended to be stained only one time.
3. Mounting Fluid, 7-mL. One dropper bottle of an aqueous, buffered, stabilized solution of glycerol (ph 8.2 ± 0.2) and 0.1% sodium azide.
4. 40X PBS Concentrate, 25-mL. One bottle containing a 40X concentrate consisting of 4% sodium azide (0.1% sodium azide after dilution to 1X using de-mineralized water) in a phosphate buffered saline (PBS) solution.

Patient samples are inoculated onto susceptible cell monolayers and cultured. After a defined incubation period, the cells to be tested for the presence of CMV-IEA are fixed in acetone. The CMV-IEA DFA Reagent is added to the cells which are then incubated for 15 to 30 minutes at 35° to 37°C, the stained cells are washed with the supplied PBS Solution (diluted), and a drop of the supplied Mounting Fluid is placed on the prepared cells. The cells are examined using a fluorescence microscope. The cells infected with CMV and expressing the CMV-IEA will have apple-green fluorescent nuclei while uninfected cells will contain no fluorescence but will be stained red by the Evans Blue counter-stain.

If no fluorescent cells are found, report result as "No cytomegalovirus detected". If fluorescent cells are found in the CMV-IEA DFA Reagent stained monolayer, report result as "Cytomegalovirus isolated by cell culture".

The provided 510(k) summary describes the D3 DFA Cytomegalovirus Immediate Early Antigen Identification Kit and its performance in comparison to predicate devices. Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state "acceptance criteria" in terms of specific numerical thresholds for positive or negative percent agreement that the sponsor had to meet to claim substantial equivalence. Instead, the study aims to show that the D3 DFA CMV-IEA ID Kit performs comparably to legally marketed predicate devices. The performance is reported as percent agreement with the comparator devices, which implicitly serves as the standard for acceptance.

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

• Total Clinical Specimens: 1060 specimens were cultured initially, with 1026 included in the final analysis after exclusions. This represents the sample size for the test set.
• Data Provenance: The clinical study involved three external clinical laboratory sites and the DHI internal laboratory.
  • Study Site 1: Collected and cultured 314 fresh specimens during August 2006.
  • Study Site 2: Cultured 300 specimens (72 fresh and 228 archival). Archival specimens were collected from June 2005 through September 2006 and stored at -70°C.
  • Study Site 3: Tested 146 fresh specimens from February 2007 through May 2007.
  • Study Site 4: Cultured 300 frozen prospectively collected archival specimens from a clinical reference laboratory in the Eastern U.S. in February 2007. These were stored at -70°C.
• Retrospective/Prospective: The study included both prospective (fresh specimens) and retrospective (archival/frozen specimens) data. Most sites included fresh specimens, while Study Site 2 and 4 specifically mention archival/frozen specimens. "Prospectively collected" for archival specimens refers to how they were collected for the archive, not necessarily how they were collected for this specific study.

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 test set. The ground truth for clinical performance was established by comparison to legally marketed predicate devices (Bartels Cytomegalovirus Immediate Early Antigen Kit and Light Diagnostics CMV Direct Immunofluorescence Assay), meaning the results from these predicate devices were used as the reference standard. The interpretation of these predicate device results would have typically been done by trained laboratory personnel, but no specific expert qualifications are provided.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for resolving discrepancies or establishing the ground truth when comparing the D3 DFA Cytomegalovirus Immediate Early Antigen Identification Kit to the comparator devices. The comparison is mainly presented as percentage agreement.

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

No multi-reader multi-case (MRMC) comparative effectiveness study, evaluating the effect size of human readers improving with AI vs. without AI assistance, was explicitly reported. This device is a diagnostic kit (fluorescent antibody test), not an AI algorithm assisting human readers. The performance is assessed by comparing its direct output to predicate devices.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

This device is a standalone diagnostic kit. Its performance, as described by the analytical and clinical studies, refers to the kit's ability to qualitatively detect and identify CMV IEA in cell cultures. The results are interpreted by trained laboratory personnel examining the stained cells under a fluorescence microscope, but the "performance" described is of the kit itself, rather than an AI or algorithm in a human-in-the-loop context.

7. Type of Ground Truth Used

The ground truth used for the clinical performance evaluation was the results obtained from legally marketed predicate devices (Bartels Cytomegalovirus Immediate Early Antigen Kit and Light Diagnostics CMV Direct Immunofluorescence Assay) when applied to cultured specimens. In the context of the analytical studies, ground truth was based on known concentrations of CMV (TCID50) in cell cultures.

8. Sample Size for the Training Set

The document does not describe a "training set" in the context of machine learning or AI models. This device is a traditional laboratory diagnostic kit utilizing monoclonal antibodies, not an AI-driven system. Therefore, there is no training set in the typical sense. The "training" for such a kit would involve optimization and validation during its development phase, but these details are not provided as a distinct "training set size."

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

Since there is no training set mentioned in the context of an AI/ML device, the concept of establishing ground truth for a training set does not apply here. The "development" of the kit would be based on well-established immunological principles and laboratory validation procedures to ensure the monoclonal antibodies are specific and effective, rather than training an algorithm on a dataset with ground truth.

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