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The Diagnostic Hybrids D3 DFA Herpes Simplex Virus Identification Kit is intended for use in the qualitative detection of human herpes simplex virus (HSV) in cell cultures by immunofluorescence using fluoresceinated monoclonal antibodies (MAbs). Negative results do not preclude an infection and should not be used as the sole basis for diagnosis, treatment or other management decisions.

Performance using direct specimen testing has not been evaluated.

The Diagnostic Hybrids D3 DFA Herpes Simplex Virus Identification Kit includes a DFA Reagent that contains a blend of four fluorescein-labeled murine monoclonal antibodies (MAbs), two directed against HSV type 1 (HSV-1) and two against HSV type 2 (HSV-2). The HSV-1 MAbs were developed using HSV-1(f) cell lysate as immunogen -- one has been determined to be directed against HSV-1 glycoprotein C1, the antigen to the other is undetermined. The HSV-2 MAbs were developed using a HSV-2 recombinant glycoprotein G immunogen.

The kit includes the following components:
• HSV DFA Reagent - A blend of fluorescein labeled murine monoclonal antibodies directed against antigens produced in HSV-infected cell culture. The buffered, stabilized, aqueous solution contains Evan's Blue as a counter-stain and 0.1% sodium azide as preservative.
• HSV Antigen Control Slides - Individually packaged control slides containing wells with cell culture derived positive and negative control cells. Each HSV positive well is identified. The negative wells contain uninfected cells. Each slide is intended to be stained only one time.
• PBS Concentrate - A 40X concentrate consisting of 4% sodium azide in phosphate buffered saline (after dilution to 1X in water, the concentration of sodium azide in the solution is 0.1%).
• Mounting Fluid - an aqueous, buffered, stabilized solution of glycerol and 0.1% sodium azide.

The cells to be tested, on a slide prepared from a tube culture or on a monolayer of cells cultured in a multi-well plate or a coverslip in a shell vial, are fixed in acetone. The HSV DFA Reagent is added to the cells to detect the presence of HSV specific viral antigens. After incubating for 15 to 30 minutes at 35° to 37°C, the stained cells are washed with the supplied Phosphate Buffered Saline (PBS). To prepare the slide for examination, a drop of the supplied Mounting Medium is added to the stained cells and a coverslip is placed on the slide. To prepare the centrifuge enhanced cell cultures for examination, a drop of Mounting Fluid is placed on a clean microscope slide. The coverslip is removed from the shell vial and placed on to the Mounting Fluid.

For multi-well plates, monolayers are fixed with an 80% aqueous acetone solution. The HSV DFA Reagent is added to the cells to detect the presence of any HSV specific viral antigens. After incubating for 15 to 30 minutes at 35° to 37°C, the stained cells are washed with the supplied Phosphate Buffered Saline (PBS). Mounting Fluid is added to each well to cover the monolayers.

The slides or wells are examined using a fluorescence microscope equipped with the correct filter combination for FITC at a magnification of 100-400X. Virus infected cells will be stained with bright apple-green fluorescence while uninfected cells will contain no apple-green fluorescence but will fluoresce red by the Evan's Blue counterstain' which is included in the HSV DFA Reagent.

If no fluorescent cells are found, report result as, "No herpes simplex virus detected". If fluorescent cells are found, report result as, "Herpes simplex virus isolated by cell culture."

Included in the kit are HSV Antigen Control Slides. A Control Slide is intended to function as an indicator that the kit reagents are working properly in the test. [The slides are prepared with wells of HSV infected cells and uninfected cells.] Positive and negative controls must demonstrate appropriate staining characteristics for specimen results to be valid. Controls may also aid in the interpretation of test results.

It is recommended that cell culture positive (infected with known HSV isolate) and negative (uninfected cells) controls be run with each assay to provide a means to ensure adequate performance of the cell culture system used. If control cultures fail to perform correctly, results are considered invalid.

Here's a breakdown of the acceptance criteria and the study details for the D3 HERPES SIMPLEX VIRUS IDENTIFICATION KIT, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance:

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

• Sample Size: 530 specimens were initially collected. After excluding 3 specimens due to bacterial contamination, 527 specimens were used for analysis.
• Data Provenance: The data was collected from four different laboratories as part of a clinical study. The information does not specify the country of origin, but the company address is in Athens, Ohio, USA, suggesting the study likely took place in the US. The study appears to be prospective as it involved comparing the D3 DFA HSV Kit performance to comparison tests using these specimens. The specimens were a combination of fresh (250) and frozen (280).

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

The document does not explicitly state the number of experts used to establish the ground truth or their specific qualifications. However, it indicates that the comparison was made against "comparison tests" which are legally marketed devices (predicates: Bartels® Herpes Simplex Virus Fluorescent Monoclonal Antibody Test, Pathodx® Herpes Typing Kit, MicroTrak® HSV 1/HSV 2 Culture Identification and Typing Test). The "comparison device" results were used as the reference against which the subject device was evaluated. It is implied that these comparison tests' results, and their interpretation, constitute the ground truth.

4. Adjudication Method for the Test Set:

The document does not explicitly describe an adjudication method for discrepancies between the subject device and the comparison device. The agreement percentages are calculated directly based on the reported positive and negative results from both the subject and comparison devices.

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

A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was NOT done in the context of human readers improving with AI vs. without AI assistance. This device is a diagnostic kit (reagent and controls) for laboratory use, specifically for immunofluorescence detection of HSV in cell cultures, not an AI-powered diagnostic tool for human interpretation.

6. Standalone (Algorithm Only) Performance:

Not applicable as this is a laboratory diagnostic kit, not an algorithm. The kit relies on a trained laboratory professional to perform the staining and interpret the results under a fluorescence microscope.

7. Type of Ground Truth Used:

The ground truth was established by comparison to legally marketed predicate devices (comparison tests). The "comparison device" results from cell cultures are considered the reference standard for the clinical performance evaluation. The clinical performance section states, "Clinical studies have been conducted at four different laboratories where they compared the D3 DFA HSV Kit performance to that of comparison tests..."

8. Sample Size for the Training Set:

The document does not mention a training set in the context of machine learning or AI. This is a traditional laboratory diagnostic kit, not an AI-driven product. The "training" for such a kit would involve laboratory personnel learning to use the kit according to its instructions.

However, if we interpret "training set" as the data used for internal development and optimization of the reagent, the analytical specificity and reactivity tests provide some insight into the range of organisms and conditions tested during development. The cross-reactivity panel included 59 viral strains, 17 host cell types, 27 bacterial cultures, 1 yeast, and 1 protozoan culture. The analytical specificity included ATCC reference HSV-1 and HSV-2 strains.

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

As mentioned, there isn't a "training set" in the AI sense. For the analytical studies (specificity, cross-reactivity), the ground truth was established by:

• Known (ATCC reference) HSV-1 and HSV-2 strains: These were confirmed positive for HSV.
• Known uninfected cell cultures: Used as negative controls and for testing specificity against various cell lines.
• Known cultures of other microorganisms (viruses, bacteria, yeast, protozoans): These were confirmed non-HSV organisms to test for cross-reactivity. The concentration of these organisms was also tested at high titers to challenge the specificity.
• Commercially available slides: Some cross-reactivity testing used commercially prepared slides for certain organisms, implying the manufacturer of those slides established their content.

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