(80 days)
The illumigene Mycoplasma Direct DNA amplification assay, performed on the illumipro-10™, is a qualitative in vitro diagnostic test for the direct detection of DNA from Mycoplasma pneumoniae in human throat swabs obtained from patients suspected of having Mycoplasma pneumoniae infection.
The illumigene Mycoplasma Direct assay utilizes loop-mediated isothermal DNA amplification (LAMP) technology to detect Mycoplasma pneumoniae by targeting a segment of the Mycoplasma pneumoniae genome.
Results from the illumigene Mycoplasma Direct DNA amplification assay should be used in conjunction with clinical presentation, other laboratory findings, and epidemiological risk factors as an aid in the diagnosis of Mycoplasma infection and should not be used as the sole basis for treatment or other patient management. Positive results do not rule out co-infection with other organisms and negative results in persons with respiratory tract infections may be due to pathogens not detected by this assay. Lower respiratory tract infections due to M. pneumoniae may not be detected by this assay. If lower respiratory tract infection due to M. pneumoniae is suspected, additional laboratory testing using methods other than the illumigene Mycoplasma Direct DNA Amplification Assay may be necessary.
The illumigene Molecular Diagnostic Test System is comprised of the illumigene® Mycoplasma Direct DNA Amplification Assay Test Kit, the illumigene Mycoplasma Direct External Controls Kit, and the illumipro-10™ Automated Isothermal Amplification and Detection System.
The illumigene Mycoplasma Direct molecular assay utilizes loop-mediated amplification (LAMP) technology to detect Mycoplasma pneumoniae in throat swab specimens. The illumigene Mycoplasma Direct kit includes illumigene Sample Preparation Apparatus III (SMP PREP II), illumigene Mycoplasma Test Devices, and Heat Treatment Tubes. The throat swab is added directly to the SMP PREP II, which contains assay control buffer. Samples processed through SMP PREP II (sample/control mixture) are heat treated to make target and control DNA available for amplification. The heat-treated sample is added to the illumigene Mvcoplasma Test Device.
The illumipro-10 heats each illumigene Mycoplasma Test Device containing prepared sample and control material, facilitating amplification of target DNA. When M. pneumoniae is present in the specimen, a 208 base pair (bp) sequence of the M. pneumoniae intracellular protease-like gene is amplified and magnesium pyrophosphate is generated. Magnesium pyrophosphate forms a precipitate in the reaction mixture. The illumipro-10 monitors the absorbance characteristics of the reaction solutions at the assay Run Start (Signal initial, S;) and at the assay Run End (Signal final, S;). The illumipro-10 calculates the change in light transmission between Run End and Run Start (S, :S, ) and compares the ratio to a fixed cut-off value for disposition of results.
Fixed cut-off values for the TEST chamber are used to report sample results. TEST chamber Sy:S, ratios less than 82% are reported as 'POSITIVE'; TEST chamber S;.S; ratios greater than or equal to 82% are reported as 'NEGATIVE'. Numerical values are not reported. Fixed cut-off values for the CONTROL chamber are used to determine validity. CONTROL chamber S; S, ratios less than 90% are considered valid and allow for reporting of TEST chamber results (POSITIVE, NEGATIVE). CONTROL chamber S;& ratios greater than or equal to 90% are considered invalid and prevent reporting of TEST chamber results. Invalid CONTROL chamber reactions are reported as 'INVALID'. More stringent cut-off criteria are applied to the CONTROL chamber reaction to ensure amplification is not inhibited, reagents are performing as intended and that sample processing was performed appropriately.
The illumigene Mycoplasma Direct External Control Kit contains a Positive Control reagent for use in routine Quality Control testing; the illumigene Sample Preparation Apparatus III reagent provided with the Mycoplasma Direct Kit serves as the External Negative Control reagents are provided to aid the user in detection of reagent deterioration, adverse environmental or test conditions, or variance in operator performance that may lead to test errors.
The provided text describes the illumigene Mycoplasma Direct DNA Amplification Assay and its performance through analytical and clinical studies. Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
The text does not explicitly state "acceptance criteria" in a separate section. However, the approval of the device indicates that the observed performance was acceptable to the FDA for substantial equivalence. For the purpose of this response, I will interpret the reported clinical performance statistics as meeting implied acceptance criteria for substantial equivalence to the predicate device.
| Performance Metric | Acceptance Criteria (Implied by Approval) | Reported Device Performance (illumigene Mycoplasma Direct) |
|---|---|---|
| Clinical Performance | ||
| Positive Percent Agreement (PPA) | High agreement with predicate device | 96.0% (24/25) (95% CI: 80.5 - 99.3%) |
| Negative Percent Agreement (NPA) | High agreement with predicate device | 97.7% (421/431) (95% CI: 95.8 - 98.7%) |
| Overall Percent Agreement (OPA) | High agreement with predicate device | 97.6% (445/456) (95% CI: 95.7 - 98.6%) |
| Invalid Rate | Low invalid rate | 0.0% (0/456) (95% CI: 0.0 - 0.8%) |
| Analytical Performance | ||
| Limit of Detection (LoD) | 95% detection probability | M. pneumoniae FH: 2350 CFU/mL; M. pneumoniae M129: 200 CFU/mL |
| Precision/Reproducibility | High agreement across sites/runs | High Negative: 100%; Low Positive: 98.9%; Moderate Positive: 100%; Negative: 96.7% |
| Cross-Reactivity | No observed cross-reactivity | No cross-reactivity with 40+ organisms/materials |
| Interference | No significant interference | Most substances no interference; Whole blood >2% invalid; Phenylephrine HCl >0.595 mg/mL false negative for low positive |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: A total of 458 prospective, de-identified human throat swab specimens were evaluated in the clinical study. Two samples were excluded, resulting in 456 eligible samples for analysis.
- Data Provenance: The clinical studies were conducted in 2015-2016 at independent clinical test sites representing three geographically distinct regions throughout the United States. The data is prospective as specimens were collected under informed consent from symptomatic patients.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
The text does not specify the number or qualifications of experts used to establish the ground truth for the test set.
4. Adjudication Method for the Test Set
The text describes that the performance of the illumigene Mycoplasma Direct assay was compared to a reference molecular in vitro diagnostic method, the illumigene Mycoplasma DNA Amplification Assay (Meridian Bioscience, Inc., Cincinnati, OH). This indicates that the predicate device serves as the ground truth or "referee" method. There is no mention of a human expert adjudication method for resolving discrepancies beyond further testing for specific samples (e.g., 4/10 samples identified positive by illumigene Mycoplasma after testing with an additional frozen sample).
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
This section is not applicable. The device is an in vitro diagnostic (IVD) assay for molecular detection, not an AI or imaging device involving human readers or interpretation of complex data by experts. Therefore, an MRMC study or assessment of human reader improvement with AI assistance is not relevant to this device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, a standalone performance evaluation was done. The illumigene Mycoplasma Direct DNA Amplification Assay is an automated system where the illumipro-10™ instrument performs the amplification and detection, and then calculates the ratio of light transmission to compare against fixed cut-off values to report results as 'POSITIVE', 'NEGATIVE', or 'INVALID'. The system operates without human interpretation of the primary result (the S_f:S_i ratio). The clinical study data (PPA, NPA, OPA) directly reflects this standalone performance.
7. The Type of Ground Truth Used (Expert Consensus, Pathology, Outcomes Data, etc.)
The ground truth for the clinical study was established by comparing the results of the illumigene Mycoplasma Direct assay to those of a reference molecular in vitro diagnostic method, the illumigene Mycoplasma DNA Amplification Assay (Meridian Bioscience, Inc.). This is a laboratory-based molecular assay, acting as the "gold standard" or highly accurate reference.
8. The Sample Size for the Training Set
The text does not explicitly state a separate "training set" sample size. The description of the assay cut-off development mentions "development optimization of characterized positive and negative clinical specimens" and that "amplification reagent concentrations are adjusted during design as needed to ensure illumigene results are aligned with clinical specimen reported results." This implies internal development and optimization using samples, but a distinct, quantified "training set" as understood in machine learning is not detailed. The 456 clinical samples mentioned are for evaluating performance against the predicate, not for training.
9. How the Ground Truth for the Training Set Was Established
Given that a specific "training set" is not explicitly defined with sample size, the method for establishing its ground truth is also not explicitly stated. However, considering the nature of the device (a molecular diagnostic assay), it is highly probable that any internal "training" or optimization samples would have their Mycoplasma pneumoniae status confirmed using highly accurate laboratory methods, similar to or including the predicate device, or other established molecular or culture-based techniques. The text mentions "development optimization of characterized positive and negative clinical specimens," implying these internal samples were well-defined for their Mycoplasma pneumoniae status.
§ 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.