Search Results

The ELVIS® HSV ID/Typing Test System is a qualitative test indicated for use in the isolation and identification of HSV from lesions and body fluids suspected of containing viable HSV-1 and/or HSV-2. Both serotypes have been isolated from various parts of the body, particularly when HSV-associated disease is indicated. Performance of this assay has not been established for use with antiviral therapy or prenatal monitoring.

The subject device provides Cells, Replacement Medium and Test Reagents for the culture, identification and typing of HSV isolated from patient specimens. It consists of ELVIS™ HSV Cells in a tube configuration [ELVIS™ HSV Gold Test, 510(k) No. K960578] and in shell vial and multiwell plate configurations [ELVIS™ HSV Test, 510(k) No. K941924],and reagents to which have been added HSV-typing monoclonal antibodies to permit the user to directly type the HSV-positive specimens. ELVIS™ HSV Cells are genetically engineered Baby Hamster Kidney cells, which, when infected with either HSV-1 or HSV-2 are induced to generate and accumulate an endogenous, intracellular bacterial enzyme, β-galactosidase. Other related viruses are not capable of inducing this enzyme. In addition to the induction of this specific enzyme, HSV infection of cells results in the formation of HSV, type-specific proteins. The presence of these proteins can be detected microscopically by their fluorescence when HSV-type-specific, fluorescent labeled antibodies are used. Thus, when HSV-infected monolayers are fixed using Solution 1 and treated with Solution 2T, which contains the chromogenic substrate for the ß-galactosidase enzyme, those cells infected with HSV are stained an indigo blue while uninfected cells remain colorless. Both type-2-specific, fluorescein labeled monoclonal antibodies and type-1-specific, non-labeled monoclonal antibodies are also incorporated in Solution 2T. This allows for the monoclonal antibodies to react with their specific antigens in the HSV-infected ELVIS™ Cells at the same time as the enzyme is causing the deposition of blue stain. After a 1 hour incubation period, which allows for these reactions to proceed in monolayers whose specimens contained viable HSV, the monolayers are examined for blue cells using standard light microscopy: those which do not contain blue cells are negative for HSV; those which contain blue cells are positive for HSV and can now be examined with a fluorescence microscope to determine the HSV type. I E fluorescent cells are seen, the HSV in the specimen is type 2; if no fluorescent cells are seen, the HSV in the specimen is type 1. This can be confirmed by treating the monolayer with Solution 3 which contains fluorescein-labeled goat-antimouse antibodies which will react with the type 1-specific monoclonal antibodies in the HSV-1 infected cells. Thus, the major change in the composition of the above legally marketed devices is the incorporation of the monoclonal antibodies into the Solution 2 which contains the chromogenic substrate for the ß-galactosidase enzyme (which has been re-named Solution 2T. Additionally, two other reagents are included with the subject device, i.e., Solution 3, the fluorescein-labeled goat-antimouse antibody, and a Buffered Glycerol Mounting Medium used on the fixed and stained monolayers, to prevent them from drying before microscopic examination for fluorescence.

Here's an analysis of the acceptance criteria and study details for the ELVIS™ HSV ID/Typing Test System, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" through numerical thresholds or specific benchmarks that the new device needed to meet. Instead, the primary focus of the study was to demonstrate substantial equivalence to a predicate device (Syva's HSV1/HSV2 Culture Identification/Typing Test). The key performance metrics reported are clinical sensitivity and specificity for the ID portion of the test, and complete agreement in typing results.

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

• Test Set Sample Size: Over 650 different clinical specimens were used across 4 different laboratories. Specifically, 218 HSV-positive specimens were tested concurrently with the laboratory's standard test (the predicate device).
• Data Provenance: Clinical specimens obtained from typical laboratory submissions for HSV testing. The document does not explicitly state the country of origin, but given the context of a US regulatory submission, it is highly likely to be from the United States. The data is prospective in nature for the concurrent testing, as sufficient residual samples were used from specimens normally submitted to the laboratories for HSV testing. For the antibody specificity testing, frozen positive clinical specimens and clinical isolates were used, implying a retrospective component for that specific part of the study.

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

The document does not explicitly state the number of experts used to establish ground truth or their specific qualifications (e.g., number of years of experience).

• Implicit Ground Truth: The "ground truth" for the comparative study was primarily established by the results of the predicate device (Syva's HSV1/HSV2 Culture Identification/Typing Test), which was the "laboratory's standard test."

4. Adjudication Method for the Test Set:

The document does not describe a formal adjudication method (e.g., 2+1, 3+1). Instead, it states that for the 218 HSV-positive specimens, there was "complete agreement in the typing results between the two tests" (the subject device and the predicate device). This implies that a consensus or arbitration mechanism was not necessary for these specific cases within the typing comparison, as there was full concordance. For the overall clinical sensitivity and specificity, the predicate device served as the reference.

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

No, an MRMC comparative effectiveness study was not done. This study focused on the standalone performance of the device compared to a predicate device, not on how human readers' performance improved with AI assistance.

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

Yes, a standalone study was done. The ELVIS™ HSV ID/Typing Test System is a diagnostic assay (a laboratory test kit) and its performance metrics (clinical sensitivity, clinical specificity, and typing agreement) are reported as the performance of the device itself, not in conjunction with human interpretation improvement. The examination of blue cells using standard light microscopy and fluorescent cells using a fluorescence microscope are part of the device's operational protocol, not a separate human interpretation task being augmented.

7. Type of Ground Truth Used:

The primary ground truth used for the clinical performance assessment was the predicate device's results (Syva's HSV1/HSV2 Culture Identification/Typing Test), which was considered the "laboratory's standard test." For defining analytical sensitivity and antibody specificity, the "specificity of the antibodies used in the subject device yield results identical to those results using the predicate device" was the benchmark. This points to a reference standard method (the predicate device) as the ground truth.

8. Sample Size for the Training Set:

The document does not report a specific sample size for a training set. This device is a diagnostic test kit based on genetically engineered cells and reagents, not a machine learning or AI algorithm that typically requires a distinct training set. The development efforts likely involved iterative testing and refinement of the reagents and protocols, but not in the sense of a machine learning "training set."

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

As there is no explicit mention of a "training set" in the context of an algorithm, the method for establishing ground truth for such a set is not described. The product development involved demonstrating that selected antibodies "yielded the same typing result as a predicate device," which would have guided the selection and formulation of reagents. This is more akin to traditional assay development and validation rather than ground truth establishment for a machine learning model.

Ask a specific question about this device