(252 days)
The EUROIMMUN Anti-Glutamate receptor (type NMDA) IFA is intended for the qualitative determination of autoantibodies against glutamate receptor (type NMDA) in human serum. It is used as an aid in the diagnosis of anti-glutamate receptor (type NMDA) autoimmune encephalitis in conjunction with other laboratory and clinical findings.
The EUROIMMUN IFA is an assay for standardized detection of anti-glutamate receptor (type NMDA) antibodies utilized in each laboratories familiar with indirect immunofluorescence. The non-transfected cells are used as a control to simplify differentiation of potential co-existing and non-specific reactivity such as ANA. The test kit consists of slides, which contain BIOCHIPs coated with glutamate receptor (type NMDA) transfected cells and non-transfected cells, fluorescein-labelled anti-human IgG (goat), a positive control for transforced volle and non new and of a negative control, a salt for preparation of PBS, Tween 20, embedding medium, cover glasses and an instruction booklet.
The acceptance criteria and study proving the device meets them are detailed below based on the provided text.
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state quantitative acceptance criteria for sensitivity and specificity. However, based on the studies presented, we can infer the desired clinical performance. The reported device performance is directly from the clinical studies.
| Metric | Acceptance Criteria (Inferred) | Reported Device Performance | Study |
|---|---|---|---|
| Sensitivity | High sensitivity (e.g., >90%) | 100.0% (Study 1) | Study 1 |
| 100.0% (Study 3) | Study 3 | ||
| 100.0% (Study 4) | Study 4 | ||
| 83.3% (Study 2) | Study 2 | ||
| Overall: 98.1% | Overall | ||
| Specificity | High specificity (e.g., >95%) | 0.0% (Study 1 - other encephalopathies) | Study 1 |
| 0.0% (Study 1 - healthy donors) | Study 1 | ||
| 0.0% (Study 4 - other encephalopathies) | Study 4 | ||
| Overall: 100.0% | Overall |
Note: The "acceptance criteria (inferred)" are based on typical expectations for diagnostic assays intended to aid in diagnosis. The document does not provide specific numerical targets prior to presenting the results.
2. Sample Sizes Used for the Test Set and Data Provenance:
The 'test set' for clinical performance was composed of samples across four clinical studies. The data provenance includes both retrospective and prospective elements.
- Study 1: 47 serum samples (29 anti-glutamate receptor (type NMDA) encephalitis, 18 other encephalopathies) from the US (Prospective, though the specific collection method isn't detailed, it implies collection for diagnostic purposes). Additionally, 100 adult healthy blood donors from Germany (Prospective/Retrospective, general population screening).
- Study 2: 2990 patients screened for encephalitis of unknown origin; 6 samples ultimately tested (6 women) from Germany (Retrospective).
- Study 3: 8 samples from patients with anti-glutamate receptor (type NMDA) encephalitis from Germany (Prospective/Retrospective, not explicitly stated).
- Study 4: 9 samples from patients with anti-glutamate receptor (type NMDA) encephalitis and 13 from patients with other encephalopathies from Italy (Prospective/Retrospective, not explicitly stated).
Combined Test Set Sample Sizes:
- Positive cases (anti-NMDA encephalitis): 29 + 5 (from 6) + 8 + 9 = 51 (overall 52 based on table summary, possibly one case from study 2 was reclassified as positive, or a rounding difference)
- Negative cases (other encephalopathies/healthy donors): 18 + 100 + 13 = 131
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 who established the ground truth for the test set. It mentions "patients diagnosed with anti-gluatamate receptor (type NMDA) encephalitis" and "controls with other encephalopathies," implying established clinical diagnoses. It also states the device is used "in conjunction with other laboratory and clinical findings," suggesting that the ground truth patients were diagnosed by a combination of clinical specialists (e.g., neurologists) and potentially other laboratory tests, but the specific expert review process for the test set is not detailed.
4. Adjudication Method for the Test Set:
The document does not describe a formal adjudication method (e.g., 2+1, 3+1) for establishing the ground truth of the test set cases. The cases are described as "patients diagnosed with," implying that their diagnosis served as the ground truth.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance:
The document describes an indirect immunofluorescent antibody assay (IFA) which is a laboratory test requiring visual interpretation by a human. However, it does not involve AI or a multi-reader, multi-case (MRMC) comparative effectiveness study of human readers with or without AI assistance. The device is not an AI-based diagnostic tool for image analysis as described in the context of improving human reader performance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
Not applicable. The device is an IFA kit, which inherently requires human interpretation of fluorescence under a microscope. It is not an algorithm that performs standalone analysis.
7. The Type of Ground Truth Used:
The ground truth used for the clinical studies appears to be based on clinical diagnosis of anti-glutamate receptor (type NMDA) encephalitis or other encephalopathies. For healthy controls, the implied ground truth is the absence of the disease. The phrase "patients diagnosed with" suggests a consensus among clinicians and potentially other diagnostic tests, but not explicitly pathology or a specific "outcomes data" in the sense of long-term follow-up beyond diagnosis.
8. The Sample Size for the Training Set:
The document does not describe a specific "training set" for the device, as it is a laboratory assay (IFA kit) rather than a machine learning or AI algorithm that requires a separate training phase with labeled data. The development of the assay likely involved internal optimization and validation, but this is not referred to as a "training set" in the context of device performance testing.
9. How the Ground Truth for the Training Set Was Established:
Not applicable, as a distinct training set (in the context of machine learning) is not described for this IFA kit.
§ 866.5660 Multiple autoantibodies immunological test system.
(a)
Identification. A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies).(b)
Classification. Class II (performance standards).