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The Alere™ i RSV assay performed on the Alere™ i Instrument is a rapid molecular in vitro diagnostic test utilizing an isothermal nucleic acid amplification technology for the qualitative detection of respiratory syncytial virus (RSV) viral RNA in direct nasopharyngeal swabs and nasopharyngeal swabs eluted in viral transport media from patients with signs and symptoms of respiratory infection. It is intended for use as an aid in the diagnosis of RSV in children

The Alere™ i RSV is a rapid, instrument-based test for the qualitative detection and differentiation of respiratory syncytial virus (RSV) viral RNA from direct nasopharyngeal swab (NPS) and NPS eluted in viral transport media from patients with signs and symptoms of respiratory infection. The Alere™ i RSV System utilizes isothermal nucleic acid amplification technology and is comprised of:

• Sample Receiver – single use, disposable containing the elution buffer
• . Test Base – single use, disposable comprising two sealed reaction tubes, each containing a lyophilized pellet
• . Transfer Cartridge – Single use, disposable for transfer of the eluted sample to the Test Base, and
• Alere™ i Instrument repeat use reader ●
  The reaction tubes in the Test Base contain the reagents required for amplification of the target nucleic acid and an internal control. Alere™ i RSV utilizes a pair of templates (similar to primers) for the specific amplification of RNA from RSV A and B, which occur in two separate reaction tubes. Each reaction tube contains a fluorescently labeled molecular beacon designed to specifically identify the amplified RNA targets. Alere™ i RSV is performed within the confinement of the Test Base, and no other part of the Alere™ i Instrument has contact with the sample during the amplification process. This minimizes the risk of instrument contamination and sample carry-over between measurements.
  To perform the assay, the Sample Receiver and Test Base are inserted into the Alere™ i Instrument and the elution buffer is automatically heated by the instrument. The sample is added to the Sample Receiver and transferred via the Transfer Cartridge to the Test Base, re-suspending the lyophilized pellets contained within the Test Base and initiating target amplification. Heating, mixing and detection by fluorescence are provided by the instrument, with results automatically reported.
  Results are displayed by the Alere™ i Instrument and are also stored in an on-board archive and are assigned to a sample ID that has been entered into the Alere™ i Instrument by the operator, and the date/time the test was performed. Data can be retrieved and downloaded by the operator at any time after testing. An external Alere™ Universal Printer can be attached via USB to the Alere™ i Instrument to print test results.

Here's a summary of the acceptance criteria and study details for the Alere™ i RSV device, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the clinical performance results needed for substantial equivalence, specifically the sensitivity and specificity values. The document presents the results directly after the methods.

Note: The document doesn't explicitly state "acceptance criteria" but presents these performance metrics as the outcome of the clinical study, implying they met the bar for substantial equivalence.

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

• Test Set Sample Size:
  • Nasopharyngeal Swab Direct: 497 evaluable specimens
  • Nasopharyngeal Swab Eluted in Viral Transport Media (VTM): 501 evaluable specimens
• Data Provenance: Multi-center, prospective clinical study conducted at nine US trial sites during the 2015-2016 respiratory season. This indicates that the data is prospective and collected in the USA.

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

The document states that the Alere™ i RSV performance was compared to "FDA-cleared PCR test" which served as the ground truth. It does not mention the use of human experts (e.g., radiologists, pathologists) to establish the ground truth for this clinical performance study. The ground truth was established by an objective laboratory test (PCR).

4. Adjudication Method for the Test Set

Not applicable. The ground truth was established by an FDA-cleared PCR test, not by human expert adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

Not applicable. This is not an imaging device or one that involves human "readers" or AI assistance in interpretation in the way a typical MRMC study would assess. It's an in vitro diagnostic test with an automated result interpretation.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the clinical performance study reported is for the standalone algorithm (device) performance. The Alere™ i Instrument automatically reports results: "Results are displayed by the Alere™ i Instrument and are also stored in an on-board archive..." There is no mention of a human-in-the-loop component for result interpretation for the performance assessment.

7. The type of ground truth used

The ground truth used for the clinical performance study was an FDA-cleared PCR test. This is an objective laboratory reference method.

8. The sample size for the training set

The document does not specify a separate training set or its sample size. The description provided is for the clinical performance study (test set) and analytical studies. For in vitro diagnostic devices, the development and training (if applicable for machine learning components) are typically internal, and the regulated submission focuses on the validation of the final locked algorithm using a distinct clinical test set.

9. How the ground truth for the training set was established

As no specific training set is detailed, information on how its ground truth was established is not provided.

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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.

Detailed Reproducibility Results (RSV):

Detailed Reproducibility Results (hMPV):

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.

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