(88 days)
The artus® Infl A/B RG RT-PCR Kit is a multiplex real time PCR in vitro diagnostic test for the qualitative detection and identification of Influenza A and Influenza B virus RNA in nasopharyngeal swab specimens using the Rotor-Gene® Q MDx instrument. The test is intended for use as an aid in the differential diagnosis of Influenza A and Influenza B viral infections in patients symptomatic for respiratory tract infection in conjunction with clinical and epidemiological risk factors. It is not intended to detect Influenza C virus.
Negative results do not preclude respiratory virus infection and should not be used as the sole basis for diagnosis, treatment or other patient management decisions.
Performance characteristics for Influenza A were established during the 2009/2010 and 2010/2011 flu seasons when Influenza A (H3N2) and Influenza A/2009 (H1N1) were the predominant Influenza A viruses in circulation. When other Influenza A viruses emerge, performance characteristics may vary.
If infection with a novel Influenza A virus is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions for novel virulent influenza viruses and sent to state or local health departments for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.
The artus Infl A/B RG RT-PCR Kit contains reagents and instructions for the detection and differentiation of Influenza A and Influenza B viral RNA in nasopharyngeal swabs of symptomatic patients.
The assay utilizes the EZ1 Advanced XL instrument with the EZ1 Advanced XL DSP Virus Card v. 1.0. and the EZ1 DSP Virus Kit (QIAGEN) for viral nucleic acid extraction. The Rotor-Gene Q MDx instrument with the artus Influenza Assay Software Package (QIAGEN) is used for amplification and detection.
Pathogen detection by the reverse transcription polymerase chain reaction (RT-PCR) is based on the reverse transcription of the RNA into complementary DNA (cDNA) and subsequent amplification of specific regions of the pathogen genome. In real-time PCR the amplified product is detected via fluorescent dyes. These are linked to oligonucleotides that bind specifically to the amplified product. Monitoring the fluorescence intensities during the PCR run (i.e., in real time) allows the detection of the accumulating product without having to re-open the reaction tubes after the PCR run.
The Influenza A/B Master contains primers, probes, enzymes, and other reaction components (except Mg solution) needed for the specific amplification of a 141 bp region of the Influenza A virus genome and a 95 bp region of the influenza virus B genome, and for the direct detection of the specific amplicons in two fluorescence channels of the Rotor-Gene O MDx instrument. The primers are complementary to highly conserved regions of the Matrix gene locus within the influenza B virus genome. The probes are dual-labeled with a reporter dye attached to the 5'-end and a quencher dye attached to the 3'-end. Detection is performed on the Rotor-Gene O MDx instrument at wavelengths listed in Table 5.1.
In addition, the Master contains a second heterologous primer/probe set to detect the Influenza A/B Internal Control (IC). The IC result identifies possible failure of RNA extraction or the presence of PCR inhibition. The Internal Control is detected in a third fluorescence channel.
An Influenza A Control and an Influenza B Control comprised of in vitro transcripts representing the amplified regions of the Influenza A virus genome and the Influenza B virus genome, respectively, are provided. PCR grade water is provided as a negative (notemplate) control.
The procedure consists of four consecutive steps:
- Sample collection: Collect nasopharyngeal swab specimens from symptomatic patients using a polyester, nylon, or rayon swab and place it into virus transport medium.
- Nucleic acid extraction: Add the Influenza IC to the carrier RNA before starting the extraction procedure. Extract viral RNA using the EZ1 DSP Virus Kit in combination with the EZ1 Advanced XL instrument.
- Real-time RT-PCR: Add the extracted RNA and positive and negative control material to Influenza A/B Master mix. Perform real-time RT-PCR using the Rotor-Gene O MDx instrument.
- Result interpretation: The Influenza Assay Package evaluates the results of the positive and negative controls to determine if the run is valid. If the run is valid, the internal control and target-specific results of each specimen are evaluated.
Here's an analysis of the acceptance criteria and supporting studies for the artus® Infl A/B RG RT-PCR Kit, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria (e.g., "Sensitivity must be >90%"). Instead, it presents the "performance characteristics" observed in the clinical evaluations. The interpretation below assumes that achieving these reported performance levels was sufficient for acceptance.
| Metric (Target) | Influenza A Reported Performance | Influenza B Reported Performance | Study Type |
|---|---|---|---|
| Sensitivity (Prospective Clinical) | 100% (95% CI: 80-100%) | 100% (95% CI: 92-100%) | Prospective Clinical Evaluation |
| Specificity (Prospective Clinical) | 95.0% (95% CI: 91-97%) | 94.7% (95% CI: 91-97%) | Prospective Clinical Evaluation |
| Positive Agreement (Retrospective Clinical 1) | 100% (No CI provided, but 175/175 detected) | 100% (95% CI: 90-100%) | Retrospective Clinical Evaluation (vs. FDA cleared molecular test) |
| Negative Agreement (Retrospective Clinical 1) | N/A (implied from 0 false negatives) | 98.9% (95% CI: 96-100%) | Retrospective Clinical Evaluation (vs. FDA cleared molecular test) |
| Positive Agreement (Retrospective Clinical 2) | 97.9% (95% CI: 93-99%) | 100% (95% CI: 79-100%) | Prospectively collected & archived clinical evaluation (vs. FDA cleared molecular test) |
| Negative Agreement (Retrospective Clinical 2) | 94.8% (95% CI: 92-97%) | 99.6% (95% CI: 98-100%) | Prospectively collected & archived clinical evaluation (vs. FDA cleared molecular test) |
| Overall Reproducibility (across 3 sites) | 99.4% (overall agreement for all panel members) | 99.4% (overall agreement for all panel members) | Non-clinical Reproducibility Study |
| Limit of Detection (LoD) | Ranged from 10e0.2 to 10e1.1 TCID50/ml for various A strains (≥95% detection rate) | Ranged from 10e-0.1 to 10e0.9 TCID50/ml for various B strains (≥95% detection rate) | Non-clinical LoD Study |
| Analytical Reactivity | All 18 Influenza A strains detected at near LoD concentrations | All 6 Influenza B strains detected at near LoD concentrations | Non-clinical Reactivity Study |
| Interfering Substances | No interference observed for tested substances, except for one instance with Mupirocin at 10 mg/ml for Influenza B (resolved at 2 mg/ml) | No interference observed for tested substances, except for one instance with Mupirocin at 10 mg/ml for Influenza B (resolved at 2 mg/ml) | Non-clinical Interfering Substances Study |
| Analytical Specificity | No false positives for 21 non-target respiratory viruses. Invalid results for Bordetella pertussis and Streptococcus pneumoniae at high concentrations (resolved at lower concentrations). | No false positives for 21 non-target respiratory viruses. Invalid results for Bordetella pertussis and Streptococcus pneumoniae at high concentrations (resolved at lower concentrations). | Non-clinical Analytical Specificity Study |
| Competitive Inhibition | Inhibition observed for A/California/7/09-like virus reference strain when B/Florida/4/2006-like virus or B/Brisbane/60/2008-like virus were present at 10e5 TCID50/ml (resolved at 10e4 TCID50/ml) | No inhibition observed for the reference influenza B strain in the presence of 7 competing Influenza A strains at 10e5 TCID50/ml | Non-clinical Competitive Inhibition Study |
| Carryover/Cross Contamination | No evidence of carryover or cross-contamination | No evidence of carryover or cross-contamination | Non-clinical Carryover/Cross Contamination Study |
2. Sample Size Used for the Test Set and Data Provenance
- Prospective Clinical Evaluation:
- Sample Size: 254 nasopharyngeal (NP) swab specimens.
- Data Provenance: Prospective, collected at 3 clinical laboratories in the United States during the 2010-11 respiratory virus season.
- Retrospective Clinical Evaluation 1:
- Sample Size: 212 specimens.
- Data Provenance: Retrospective, collected from the 2009 and 2010 respiratory virus season. Country of origin not explicitly stated but implied to be US clinical laboratories where initial testing occurred.
- Prospectively Collected and Archived Clinical Evaluation (Retrospective Clinical 2):
- Sample Size: 462 well-characterized, de-identified, residual specimens.
- Data Provenance: Retrospective (archived), collected from August 2009 to May 2011 respiratory virus season. Country of origin not explicitly stated but implied to be US clinical settings.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the "number of experts" or their "qualifications" for establishing the ground truth in the clinical studies.
- Prospective Clinical Evaluation: The reference method was "standard viral culture (shell vial) followed by direct fluorescent antibody (DFA) screening and identification." This typically involves trained laboratory personnel (e.g., microbiologists, lab technologists) rather than a panel of clinical experts for interpretation. Bidirectional sequencing was used to confirm some discrepant results.
- Retrospective Clinical Evaluation 1 & 2: The ground truth was established using "an FDA cleared molecular test" or "FDA cleared molecular tests for routine patient management." This implies reliance on the validated results from these predicate devices, not on a panel of human experts re-interpreting raw data.
4. Adjudication Method for the Test Set
The document does not describe a formal adjudication method (e.g., 2+1, 3+1) involving multiple experts for the test set.
- In the prospective study, discrepant results (artus positive, culture negative) were investigated using "bidirectional sequencing." This is a molecular confirmation, not an expert panel adjudication.
- In the retrospective studies, the "FDA cleared molecular tests" were used as the reference, suggesting agreement with those established results was the primary measure, not a separate adjudication process.
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
No, an MRMC comparative effectiveness study was not done. This device is a molecular diagnostic test (RT-PCR kit), not an imaging or AI-assisted diagnostic tool that would typically involve human "readers" or assess improvement with AI assistance. The performance is entirely based on the kit's analytical and clinical accuracy.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the performance reported for the artus® Infl A/B RG RT-PCR Kit is inherently standalone (algorithm only, without human-in-the-loop performance in the sense of interpretative assistance). The device outputs a qualitative positive/negative result for Influenza A and B. While human operators are involved in sample preparation and running the assay, the "results interpretation" step involves the "Influenza Assay Package evaluating the results of the positive and negative controls to determine if the run is valid" and then evaluating the "internal control and target-specific results of each specimen." This is an automated interpretation by the device's software package based on pre-defined thresholds.
7. The Type of Ground Truth Used
- Prospective Clinical Evaluation: The primary ground truth was standard viral culture (shell vial) followed by direct fluorescent antibody (DFA) screening and identification. For discrepant results, bidirectional sequencing was used as a confirmatory method.
- Retrospective Clinical Evaluation 1 & 2: An FDA cleared molecular test was used as the ground truth (reference method).
8. The Sample Size for the Training Set
The document does not specify a "training set" or its sample size. For molecular diagnostic kits like this, the "development" or "training" phase usually refers to the analytical studies (e.g., determining optimal primer/probe concentrations, establishing LoD, testing specificity and reactivity) and initial method validation, rather than a distinct 'training set' for an algorithm in the way it's used for AI/machine learning. The provided data focuses on the performance of the finalized device.
9. How the Ground Truth for the Training Set Was Established
Since no specific "training set" is identified for the device in the context of an algorithm, the concept of establishing ground truth for it is not applicable here. The ground truth for the performance evaluation (test sets) was established as described in section 7. The analytical parameters of the assay (e.g., target genes, detection channels, controls) are designed and experimentally validated, not "trained" on a dataset with external ground truth in the AI sense.
§ 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.