(29 days)
The DiaSorin Molecular Simplexa™ Bordetella Direct assay is an in vitro diagnostic test intended for use on the LIAISON® MDX instrument for the qualitative detection and differentiation of Bordetella pertussis and Bordetella parapertussis nucleic acids from nasopharyngeal swab (NPS) specimens from patients with signs and symptoms of Bordetella infection of the respiratory tract.
The Simplexa™ Bordetella Direct assay is performed on the LIAISON® MDX instrument and utilizes real-time PCR amplification to detect B. pertussis by targeting the IS481 insertional element of the B. pertussis genome and to detect B. parapertussis by targeting the IS1001 insertional element of the B. parapertussis genome. The IS481 insertional element can also be present in B. holmesii and B. bronchiseptica. Specimens collected from patients with respiratory infection caused by B. pertussis, B. holmesii or B. bronchiseptica may yield positive test results in IS481 assays. B. holmesii infection may cause clinical illness similar to B. pertussis, and mixed outbreaks involving both B. pertussis and B. holmesii infection have been reported. Additional testing should be performed if necessary to differentiate B. holmesii and B. pertussis. B. bronchiseptica is a rare cause of infection in humans. When clinical factors suggest that B. pertussis may not be the cause of respiratory infection, other clinically appropriate investigation(s) should be carried out in accordance with published guidelines.
Negative results for the Simplexa™ Bordetella Direct assay do not preclude Bordetella infection and positive results do not rule out co-infection with other respiratory pathogens. Results from the Simplexa™ Bordetella Direct assay should be used with other clinical findings and epidemiological information as an aid in diagnosis of Bordetella infection. Test results should not be used as the sole basis for treatment or other patient management decisions.
Simplexa™ Bordetella Positive Control Pack
The Simplexa™ Bordetella Positive Control Pack is intended to be used as a control with the Simplexa™ Bordetella Direct kit.
This control is not intended for use with other assays or systems.
The Simplexa™ Bordetella Direct assay system is a real-time PCR assay that enables the direct amplification, detection and differentiation of Bordetella pertussis and Bordetella parapertussis DNA from unprocessed nasopharyngeal swabs (NPS) without nucleic acid extraction. The system consists of the Simplexa™ Bordetella Direct assay, the LIAISON® MDX (with LIAISON® MDX Studio Software), the Direct Amplification Disc and associated accessories.
In the Simplexa™ Bordetella Direct assay, primers and fluorescent probes are used together to amplify and detect Bordetella pertussis, Bordetella parapertussis and internal control targets. Insertion sequences IS481 and IS1001 are targeted to identify Bordetella pertussis and Bordetella parapertussis DNA respectively in the specimen. An internal control is used to detect PCR failure and/or inhibition.
The provided text details the 510(k) summary for the Simplexa™ Bordetella Direct and Simplexa™ Bordetella Positive Control Pack, specifically focusing on the update to include fresh nasopharyngeal swab (NPS) samples. While the document mentions "acceptance criteria" and "design inputs" for the validation, it does not explicitly state the quantitative acceptance criteria for device performance (e.g., specific thresholds for PPA and NPA) in the provided sections. Instead, it presents the results of the clinical studies.
However, based on the provided data, we can infer that 100% PPA and a high NPA (above 95%) were considered acceptable, given the reported results.
Here's a breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance
As stated, the document does not explicitly list the acceptance criteria as specific numerical targets for PPA and NPA (e.g., "PPA must be ≥ 95%"). However, the reported performance is provided. We can infer that the observed performance was deemed acceptable by the FDA for the device's clearance.
| Metric (for Bordetella pertussis) | Acceptance Criteria (inferred, as not explicitly stated) | Reported Device Performance |
|---|---|---|
| Positive Percent Agreement (PPA) | High agreement (e.g., ≥90% or 100%) | 100.0% (36/36) |
| Negative Percent Agreement (NPA) | High agreement (e.g., ≥95%) | 97.9% (326/333) |
| Metric (for Bordetella parapertussis) | Acceptance Criteria (inferred, as not explicitly stated) | Reported Device Performance |
|---|---|---|
| Positive Percent Agreement (PPA) | High agreement (e.g., ≥90% or 100%) | 100.0% (2/2) |
| Negative Percent Agreement (NPA) | High agreement (e.g., ≥95%) | 100.0% (174/174) |
Note: The confidence intervals are provided in the source document but are not included in this table for brevity.
2. Sample Size Used for the Test Set and Data Provenance
Bordetella pertussis (Fresh Samples):
- Sample Size: 369 evaluable fresh samples.
- Data Provenance: Prospectively collected from five (5) geographically diverse sites in the US (inferred, as it's an FDA submission for a US company) from May 2018 to October 2018, from patients with signs and symptoms of Bordetella infection.
Bordetella parapertussis (Fresh Samples):
- Sample Size: 176 evaluable fresh samples (out of 178 collected).
- Data Provenance: Prospectively collected from six (6) geographically diverse sites in the US (inferred) between July 2017 and August 2017, from patients with signs and symptoms of Bordetella infections.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not specify the number of experts or their qualifications used to establish the ground truth.
4. Adjudication Method for the Test Set
- For B. pertussis (Table 3): The reference method was an "FDA Cleared NAAT" (Nucleic Acid Amplification Test). The document does not describe the adjudication method if results between different reference tests varied or whether a composite ground truth derived from multiple tests was used, other than referencing a single FDA cleared NAAT.
- For B. parapertussis (Table 4): The reference method was a "composite reference method" consisting of "two well-characterized real-time PCR assays followed by confirmation of positive PCR amplification products with bidirectional sequencing, per target." Samples were characterized as positive if one or both composite reference methods were positive and confirmed by bi-directional sequencing. Samples were characterized as negative if both composite reference methods were negative. This describes an adjudication method that combines results from multiple tests.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, a MRMC comparative effectiveness study was not done. This device is an in vitro diagnostic (IVD) test for qualitative detection of nucleic acids, not an imaging device requiring human reader interpretation. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
Yes, the performance presented is standalone algorithm performance. The Simplexa™ Bordetella Direct assay is an automated real-time PCR assay performed on the LIAISON® MDX instrument, which provides automated test interpretation and report generation. There is no human-in-the-loop performance described for the diagnostic decision-making process based on the assay's output.
7. The Type of Ground Truth Used
- For B. pertussis (Table 3): The ground truth was established by an "FDA Cleared reference method testing."
- For B. parapertussis (Table 4): The ground truth was established by a "composite reference method" combining two well-characterized real-time PCR assays and bidirectional sequencing confirmation. This is a form of expert-defined molecular diagnostic ground truth.
8. The Sample Size for the Training Set
The document does not provide information on a specific training set size. The studies described are for "Method Comparison" using prospectively collected samples, which typically serve as validation or test sets for device performance rather than training sets. For molecular diagnostic assays like this, the "training" usually involves optimizing primer/probe design and assay conditions, which isn't described in terms of a "training set" with ground truth in the same way an AI/ML model would be.
9. How the Ground Truth for the Training Set was Established
As no training set is described in the provided document, the method for establishing its ground truth is also not applicable/not provided.
§ 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.