(78 days)
The Quidel Molecular RSV + hMPV Assay is a multiplex Real-Time PCR (RT-PCR) assay for the qualitative detection and identification of respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) ribonucleic acid (RNA) extracted from nasal and nasopharyngeal swab specimens from patients with signs and symptoms of respiratory infection. This in vitro diagnostic test is intended to aid in the differential diagnosis of RSV and hMPV infections in humans in conjunction with clinical and epidemiological risk factors. This test is not intended to differentiate the two subtypes of RSV or the four genetic sub-lineages of hMPV.
Negative results do not preclude RSV infection and/or hMPV infection and should not be used as the sole basis for diagnosis, treatment or other patient management decisions.
Conversely, positive results do not rule-out bacterial infection or co-infection with other viruses. The agent detected may not be the definite cause of disease. The use of additional laboratory testing and clinical presentation must be considered in order to obtain the final diagnosis of respiratory viral infection.
The Quidel Molecular RSV + hMPV Assay can be performed using either the Life Technologies QuantStudio™ Dx RT-PCR Instrument, the Applied Biosystems® 7500 Fast Dx RT-PCR Instrument, or the Cepheid SmartCycler® II System.
The Quidel Molecular RSV + hMPV Assay detects viral nucleic acids that have been extracted from a patient sample using the bioMérieux NucliSENS easyMAG automated extraction platform. A multiplex RT-PCR reaction is carried out under optimized conditions in a single tube generating amplicons for each of the target viruses present in the sample. This reaction is performed utilizing the Cepheid SmartCycler II, the Applied Biosystems 7500 Fast Dx. or the Life Technologies QuantStudio Dx. Identification of RSV, hMPV, and the process control (PRC) occurs by the use of target-specific primers and fluorescent-labeled probes that hybridize to conserved regions in the genomes of RSV and hMPV and the PRC.
Acceptance Criteria and Study for Quidel Molecular RSV + hMPV Assay
1. Table of Acceptance Criteria and Reported Device Performance
The provided document does not explicitly state pre-defined acceptance criteria (e.g., minimum PPA/NPA percentages or specific LoD values that must be met for approval). However, it implicitly demonstrates acceptable performance by comparing the device to FDA-cleared predicate devices and presenting the results of analytical and clinical studies. We can infer the "reported device performance" from the "Combined Clinical Site Data" table.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (RSV) | Reported Device Performance (hMPV) |
|---|---|---|---|
| Clinical Positive Percent Agreement (PPA) | High agreement with predicate device | 93.8% (95% CI: 87.7% to 96.9%) | 98.2% (95% CI: 90.6% to 99.7%) |
| Clinical Negative Percent Agreement (NPA) | High agreement with predicate device | 98.1% (95% CI: 96.7% to 99.0%) | 99.4% (95% CI: 98.4% to 99.8%) |
| Reproducibility (Detection %) | Consistent detection at various viral loads across sites | See detailed tables below for RSV and hMPV at different LoD multiples | See detailed tables below for RSV and hMPV at different LoD multiples |
| Limit of Detection (LoD) | Low concentration for reliable detection (95% positivity) | RSV A: 6.29E-01 TCID50/mL, RSV B: 2.25E-01 TCID50/mL | hMPV-A1: 8.73E+00 TCID50/mL, hMPV-A2: 2.91E+00 TCID50/mL, hMPV-B1: 2.25E+00 TCID50/mL, hMPV-B2: 2.25E+00 TCID50/mL |
Detailed Reproducibility Results (RSV):
| Panel Member ID | Detection % (Combined Sites) | Average Ct (Combined Sites) | %CV (Combined Sites) |
|---|---|---|---|
| RSV Medium Positive (5x LoD) | 100% | 30.6 | 4% |
| RSV Low Positive (2x LoD) | 98.9% | 33.1 | 6% |
| RSV High Negative (0.3x LoD) | 43.3% | 37.1 | 4% |
| RSV Negative | 0% | N/A | N/A |
| RSV Positive Control | 100% | 31.9 | 7% |
| RSV Negative Control | 0% | N/A | N/A |
Detailed Reproducibility Results (hMPV):
| Panel Member ID | Detection % (Combined Sites) | Average Ct (Combined Sites) | %CV (Combined Sites) |
|---|---|---|---|
| hMPV Medium Positive (5x LoD) | 100% | 28.6 | 3% |
| hMPV Low Positive (2x LoD) | 100% | 30.3 | 3% |
| hMPV High Negative (0.15x LoD) | 57.8% | 36.0 | 4% |
| hMPV Negative | 0% | N/A | N/A |
| hMPV Positive Control | 100% | 28.3 | 3.0% |
| hMPV Negative Control | 0% | N/A | N/A |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size:
- RSV: 700 nasal or nasopharyngeal swab specimens (after removing 13 invalid specimens from an initial 713).
- hMPV: 707 nasal or nasopharyngeal swab specimens (after removing 6 invalid specimens from an initial 713).
- Data Provenance: Prospective study conducted during the 2013 respiratory virus season (January to March 2013) at three sites across the United States.
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 performance study was established by two FDA-cleared RT-PCR assays (Prodesse ProFlu+ and Pro hMPV+), rather than human experts. Thus, information about the number and qualifications of experts is not applicable to this study design.
4. Adjudication Method for the Test Set
The ground truth was established by two FDA-cleared predicate RT-PCR assays. The document does not describe an explicit adjudication method between these predicate devices or between the predicate devices and an independent reference standard. For each virus (RSV and hMPV) separately, the results of the Quidel Molecular assay were compared directly against the respective predicate device's results.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This study compares the performance of a molecular diagnostic assay against other molecular diagnostic assays, not the performance of human readers with and without AI assistance.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the study describes the "standalone" performance of the Quidel Molecular RSV + hMPV Assay. It is a molecular diagnostic test that produces a qualitative result (positive/negative) based on the detection of viral nucleic acids through RT-PCR, without human interpretation of complex images or data that would typically involve a "human-in-the-loop" decision process. The output is directly generated by the instrument based on the fluorescent signal.
7. The Type of Ground Truth Used
The ground truth for the clinical performance study was established using comparison to FDA-cleared RT-PCR predicate devices. Specifically:
- For RSV, the predicate device was Prodesse ProFlu+.
- For hMPV, the predicate device was Prodesse Pro hMPV+.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" for the purpose of algorithm development or machine learning in the conventional sense. This is a molecular diagnostic assay where primers and probes are designed to target specific viral genes. The "development" of the assay involves optimizing reaction conditions, not training a machine learning model. Therefore, providing a sample size for a training set in this context is not applicable.
9. How the Ground Truth for the Training Set Was Established
As noted above, the concept of a "training set" for this type of molecular diagnostic assay is not directly applicable. The "ground truth" for developing the analytical performance characteristics (like LoD, inclusivity, specificity) would have been established through controlled laboratory experiments using known quantities and strains of viruses, and known negative samples. These are standard methods in the development of PCR-based diagnostics.
§ 866.3980 Respiratory viral panel multiplex nucleic acid assay.
(a)
Identification. A respiratory viral panel multiplex nucleic acid assay is a qualitative in vitro diagnostic device intended to simultaneously detect and identify multiple viral nucleic acids extracted from human respiratory specimens or viral culture. The detection and identification of a specific viral nucleic acid from individuals exhibiting signs and symptoms of respiratory infection aids in the diagnosis of respiratory viral infection when used in conjunction with other clinical and laboratory findings. The device is intended for detection and identification of a combination of the following viruses:(1) Influenza A and Influenza B;
(2) Influenza A subtype H1 and Influenza A subtype H3;
(3) Respiratory Syncytial Virus subtype A and Respiratory Syncytial Virus subtype B;
(4) Parainfluenza 1, Parainfluenza 2, and Parainfluenza 3 virus;
(5) Human Metapneumovirus;
(6) Rhinovirus; and
(7) Adenovirus.
(b)
Classification. Class II (special controls). The special controls are:(1) FDA's guidance document entitled “Class II Special Controls Guidance Document: Respiratory Viral Panel Multiplex Nucleic Acid Assay;”
(2) For a device that detects and identifies Human Metapneumovirus, FDA's guidance document entitled “Class II Special Controls Guidance Document: Testing for Human Metapneumovirus (hMPV) Using Nucleic Acid Assays;” and
(3) For a device that detects and differentiates Influenza A subtype H1 and subtype H3, FDA's guidance document entitled “Class II Special Controls Guidance Document: Testing for Detection and Differentiation of Influenza A Virus Subtypes Using Multiplex Nucleic Acid Assays.” See § 866.1(e) for the availability of these guidance documents.