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The artus HSV-1/2 QS-RGQ MDx Kit is an in vitro real-time PCR DNA amplification assay performed on the QIAsymphony RGQ MDx system for the direct qualitative detection and differentiation of herpes simplex virus (HSV-1 and HSV-2) DNA in genital or oral vesicular lesions from male and female patients suspected of HSV infection.

The assay is intended for use as an aid in diagnosis of HSV infection in symptomatic patients.

Warning: The artus HSV-1/2 QS-RGQ MDx Kit is not FDA-cleared for use with cerebrospinal fluid (CSF) or for prenatal screening.

The artus HSV-1/2 QS-RGQ MDx Kit is an in vitro PCR assay for the qualitative detection and differentiation of nucleic acids encoding the Glycoprotein D and UL30 genes isolated from HSV-1 and HSV-2 DNA present in genital or oral lesions from male and female patients. Samples are extracted and prepared for PCR using the QIAsymphony SP/AS instrument with the QIAsymphony DSP Virus/Pathogen Mini Kit. Amplification and detection are carried out using the artus HSV-1/2 QS-RGQ MDx Kit with the Rotor-Gene O MDx (RGO MDx) and Rotor-Gene AssayManager software. The presence of a HSV-1 or HSV-2 target sequence is indicated by the fluorescent signal generated through the use of fluorescently labeled oligonucleotide probes. The probes do not generate a signal unless they are specifically bound to the amplified product. The amplification cycle at which fluorescent signal is detected by the RGQ MDx is inversely proportional to the HSV-1 and/or HSV-2 target concentration present in the original specimen. A plasmid construct containing DNA unrelated to HSV-1 and HSV-2 is introduced into each specimen during sample preparation to serve as an internal control. Run as a separate control, the positive control serves to demonstrate that the HSV-1/2 PCR reagents are functional. In addition, the positive control functions as a process control, to demonstrate that sample preparation has proceeded correctly during the run.

The provided documentation describes the performance characteristics and clinical study results for the artus® HSV-1/2 QS-RGQ MDx Kit, an in vitro real-time PCR assay for the detection and differentiation of HSV-1 and HSV-2 DNA.

Here's an analysis of the acceptance criteria and the study that proves the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are generally qualitative for this type of diagnostic device, revolving around achieving sufficient sensitivity and specificity compared to a predicate device or established methods. The reported device performance is detailed in the tables under "Performance Characteristics - Clinical Studies."

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

• Clinical Study (Prospective):

  • Genital Samples: 510 total specimens (initially), from which 96 HSV-2 positive samples by ELVIS culture were removed for HSV-1 calculation, resulting in 414 for HSV-1 analysis. All 510 were used for HSV-2.
  • Oral Samples: 152 total specimens.
  • Mucocutaneous Samples: 281 for HSV-1, 320 for HSV-2 (a subset of the overall clinical study samples).
  • Data Provenance: Prospectively collected from symptomatic patients at 3 testing sites. Samples were from 5 geographically diverse locations within the United States.

• Contrived Sample Study (for HSV-2 in Oral Samples):

  • Sample Size: 70 individual samples (15 HSV-1/2 negative oral, 10 HSV-1 positive oral, 45 HSV-1/2 negative oral spiked with HSV-2).
  • Data Provenance: Prepared using oral samples from the method comparison study, spiked with HSV-2 at various concentrations.

• Analytical Reactivity Test Set: 39 strains (20 HSV-1, 19 HSV-2) from Zeptometrix™ Corporation (ZMC).

• Cross-Reactivity and Microbial Interference Test Set: A panel of 45 microorganisms (bacteria, fungi, viruses) with listed sources.

• Precision Test Sets:

  • Within-Laboratory: Not explicitly stated, but 7-member panel tested in replicates of three, once a day for 12 days (approx. 36 replicates per panel member).
  • Site-to-Site Reproducibility: 7-member panel run by 2 users at each of 3 external sites, 5 runs on alternating days (total of 90 test results per panel member).

• Interfering Substances Test Set: 24 substances.

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

The ground truth for the clinical study was established using the ELVIS® (Enzyme Linked Virus Inducible System) HSV ID and D3 Typing Test System. This is a commercially available viral culture system, which is a recognized method for HSV detection and typing. There is no mention of human experts directly establishing primary ground truth for the clinical samples.

For discordant results in the clinical study, alternative PCR followed by bi-directional sequencing was used as a "confirmatory" method. The document does not specify the number or qualifications of experts involved in running or interpreting these alternative PCR and sequencing results.

4. Adjudication Method for the Test Set

The primary comparison was between the artus HSV-1/2 QS-RGQ MDx Kit and the ELVIS viral culture system.

For discordant results (where the artus kit and ELVIS culture disagreed):

• Discordant specimens were analyzed by alternative PCR followed by bi-directional sequencing. The results of this alternative method were then used to adjudicate the initial discrepancy and determine agreement with either the artus kit or ELVIS. The text generally states that the alternative PCR results "agreed with the artus HSV-1/2 QS-RGQ MDx result" for a certain number of samples, suggesting this method was considered the definitive truth for these specific discordant cases.

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

No multi-reader multi-case (MRMC) comparative effectiveness study was done. This device is an in-vitro diagnostic (IVD) assay, and its performance is evaluated against established laboratory methods, not typically against human reader performance in a diagnostic imaging or pathology context that would warrant an MRMC study.

6. Standalone Performance

Yes, standalone performance was done. The entire set of clinical data (sensitivity, specificity, PPV, NPV) and analytical data (LoD, reactivity, cross-reactivity, precision, interference, carryover) presented describes the performance of the artus HSV-1/2 QS-RGQ MDx Kit algorithm/system only without human intervention beyond standard laboratory operation. There is no "human-in-the-loop" component described for interpretation of results from this PCR assay.

7. Type of Ground Truth Used

The primary ground truth used for the clinical validation was:

• Viral Culture: Specifically, the ELVIS® (Enzyme Linked Virus Inducible System) HSV ID and D3 Typing Test System. This is a laboratory-based method.
• Reference Molecular Method for Discordants: For samples where the artus kit and ELVIS culture disagreed, alternative PCR followed by bi-directional sequencing was used as a secondary, more definitive ground truth.

8. Sample Size for the Training Set

The document does not explicitly state the sample size for a "training set." This type of premarket notification (510(k)) focuses on validation and clinical performance of a developed product, rather than the development process involving explicit training sets for algorithms. The device is a PCR assay, typically developed and optimized through analytical studies, rather than machine learning training.

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

Since no explicit "training set" is mentioned in the context of machine learning, there is no description of how ground truth for such a set was established. Development of PCR assays involves extensive analytical testing (e.g., optimization of primers, probes, reaction conditions) using characterized reference materials and often challenging clinical samples, which are analogous to establishing performance during the development phase.

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