(39 days)
The Prodesse® ProParaflu®+ Assay is a multiplex Real-Time PCR (RT-PCR) in vitro diagnostic test for the qualitative detection and discrimination of Parainfluenza 1 Virus, Parainfluenza 2 Virus and Parainfluenza 3 Virus (HPIV-1. HPIV-2 and HPIV-3) nucleic acids isolated and purified from nasopharvngeal (NP) swab specimens obtained from individuals exhibiting signs and symptoms of respiratory tract infections. This Assay targets the conserved regions of the Hemagglutinin-Neuraminidase (HN) gene of HPIV-1, HPIV-3, respectively. The detection and discrimination of HPIV-1, HPIV-2 and HPIV-3 nucleic acids from symptomatic patients aid in the diagnosis of human respiratory tract parainfluenza infections if used in conjunction with other clinical and laboratory findings. This test is not intended to detect Parainfluenza 4a or Parainfluenza 4b Viruses.
Negative test results are presumptive and should be confirmed by cell culture. Negative results do not preclude Parainfluenza 1, 2 or 3 virus infections and should not be used as the sole basis for treatment or other management decisions.
The ProParaflu+ Assay enables detection and differentiation of Parainfluenza 1 Virus. Parainfluenza 2 Virus, Parainfluenza 3 Virus and internal control nucleic acid. Nasopharyngeal swab specimens are collected from patients with signs and symptoms of a respiratory infection using a polyester, rayon or nylon tipped swab and placed into viral transport medium.
A Universal Internal Control (UIC) is added to each sample prior to nucleic acid isolation to monitor for inhibitors present in the specimens. The isolation and purification of the nucleic acids is performed using either a MagNA Pure LC Instrument (Roche) and the MagNA Pure Total Nucleic Acid Isolation Kit (Roche) or a NucliSENS® easyMAG™ System (bioMérieux) and the Automated Magnetic Extraction Reagents (bioMérieux).
The purified nucleic acids are added to ProParaflu+ Supermix along with enzymes included in the ProParaflu+ Assay Kit. The ProParaflu+ Supermix contains oligonucleotide primers and target-specific oligonucleotide probes. The primers are complementary to highly conserved regions of genetic sequences for these respiratory viruses. The probes are dual-labeled with a reporter dye attached to the 5'-end and a quencher dye attached to the 3'-end.
Reverse transcription of the RNA in the sample into complementary DNA (cDNA) and subsequent amplification of DNA is performed in a Cepheid SmartCycler® II instrument. In this process, the probe anneals specifically to the template followed by primer extension and amplification. The ProParaflu+ Assay is based on Taqman chemistry, which utilizes the 5 - 3 ' exonuclease activity of the Taq polymerase to cleave the probe thus separating the reporter dye from the quencher. This generates an increase in fluorescent signal upon excitation from a light source. With each cycle, additional reporter dve molecules are cleaved from their respective probes, further increasing fluorescent signal. The amount of fluorescence at any given cycle is dependent on the amount of amplification products present at that time. Fluorescent intensity is monitored during each PCR cycle by the SmartCycler II instrument.
The provided document describes a special 510(k) submission for the Gen-Probe Prodesse, Inc. Prodesse® ProParaflu®+ Assay (K132238). This submission focuses on modifications to an existing device (predicate device K091053, ProParaflu 101+ Assay) rather than a completely new device. Therefore, the details provided about acceptance criteria and study designs are predominantly related to demonstrating substantially equivalent performance with the modifications, rather than establishing initial performance for a novel diagnostic.
Here's an analysis of the provided information:
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state numerical "acceptance criteria" in the format of a threshold to be met. Instead, it describes the objective of the verification/validation studies for the modified device: to ensure that the modifications did not negatively impact the device's ability to detect target organisms at the limit of detection or change its clinical performance. The reported performance is framed as meeting these objectives and demonstrating substantial equivalence to the previous device.
| Acceptance Criterion Objective (Implicit) | Reported Device Performance |
|---|---|
| The Universal Internal Control (UIC) should not affect the ability of the ProParaflu+ Assay to detect target organisms at the limit of detection. | "The UIC did not affect the ability of the ProParaflu+ Assay to detect target organisms at the limit of detection as evinced by the results of Analytical Sensitivity, IC Interference, Extractor Equivalency, and Sample Stability studies." |
| The incorporation of the UIC should not change the clinical performance of the ProParaflu+ Assay. | "Additionally, the results of a retrospective clinical comparison study demonstrated the modified ProParaflu+ Assay with UIC continues to meet the performance claims for the current ProParaflu+ Assay." (Implicitly, the clinical performance did not change negatively). |
| The positive control, provided "at use" concentration, should continue to monitor for global assay failures and maintain stability. | "A Positive Control Effectiveness Study demonstrated the positive control's continued ability to monitor for global assay failures at the increased testing concentration." (Implicitly, the performance of the positive control was maintained). |
| All clinical and analytical performance/functionality should remain unchanged from the previous device. (Overall objective of verification/validation studies for modifications) | "Verification and validation studies performed demonstrated that all clinical and analytical performance/functionality remains unchanged from the previous device." (This is a summary statement of the overall outcome, not a specific performance metric). |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: The document mentions a "retrospective clinical comparison study" for the UIC modification but does not specify the sample size for this study or any other test sets.
- Data Provenance: The document states "nasopharyngeal (NP) swab specimens obtained from individuals exhibiting signs and symptoms of respiratory tract infections." The country of origin is not specified but is implied to be within the scope of where Gen-Probe Prodesse, Inc. operates (Waukesha, WI, USA, suggests data from the USA). The clinical comparison study is explicitly stated to be retrospective.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
This information is not provided in the document. As this is an in vitro diagnostic device, the ground truth is typically established by other laboratory methods rather than expert interpretation of images or other subjective data.
4. Adjudication Method for the Test Set
This information is not provided in the document. Given that it's an in vitro diagnostic test, the concept of expert adjudication in the same way it applies to image analysis might not be directly relevant. The "ground truth" would likely be determined by a different gold standard assay or cell culture, not a consensus of human reviewers of the device's output.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
An MRMC study is not applicable and was not done. This device is an in vitro diagnostic for detecting viral nucleic acids, not an imaging device requiring human reader interpretation.
6. Standalone Performance (Algorithm Only Without Human-in-the-Loop)
The device is an in vitro diagnostic Real-Time PCR assay. Its operation is inherently "standalone" in the sense that the assay itself generates a result (presence/absence of viral nucleic acid) based on the biochemical reaction and instrument detection. There isn't a "human-in-the-loop" component in the interpretation of the RT-PCR output itself, though a human performs the test and interprets the final qualitative result (positive/negative) from the instrument's readout. The performance studies (Analytical Sensitivity, IC Interference, Extractor Equivalency, Sample Stability, and the retrospective clinical comparison) demonstrate this standalone performance.
7. Type of Ground Truth Used
The document mentions that negative test results are presumptive and should be confirmed by cell culture. This indicates that cell culture is considered a gold standard or a primary method for confirming negative findings, and likely forms part of the "ground truth" for clinical evaluations. For positive results, the ground truth would typically be established by clinical diagnosis and/or comparison to a known highly sensitive and specific comparator assay or other reference methods in the clinical comparison study.
8. Sample Size for the Training Set
The document does not provide any information about a training set. As this is a molecular diagnostic assay using primers and probes targeting specific gene sequences, the "training" aspect is built into the assay design (selecting highly conserved regions) rather than a machine learning training paradigm with a specific dataset.
9. How the Ground Truth for the Training Set Was Established
Since there is no mention of a "training set" in the context of machine learning, this question is not applicable. The "ground truth" for the assay's design (e.g., confirming the suitability of the chosen gene targets and primer/probe sequences) would have been established through bioinformatics analysis and empirical testing with characterized viral isolates.
§ 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.