(60 days)
This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of circulating IgM antibodies to ß2 Glycoprotein in human serum. The presence of these antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of Primary and Secondary Antiphospholipid Syndrome.
An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of IgM antibodies to ß, Glycoprotein I in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified human ß, glycoprotein has been attached to the inner surfaces of the microwell plate. During the initial incubation step, specific antibodies in patient serum will bind to the antigen and are immobilized on the surface. After incubation and a wash step, a peroxidase labeled anti human IgM (u chain specific) second antibody is added to the wells to react with the immobilized anti beta 2 GP1 antibodies. After incubation and another wash step, the substrate is added. In the wells where the specific antigenantibody-HRP complex remains bound, the peroxidase enzyme catalyzes a color change in the substrate. After the enzymatic reaction is stopped, the colored product is read in an EIA plate reader at a specified wavelength.
Here's a breakdown of the acceptance criteria and study information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state formal "acceptance criteria" in terms of pre-defined thresholds for sensitivity, specificity, or agreement. Instead, it presents performance results from various studies and concludes that these results "support the claim that the proposed device is capable of effectively detecting IgM antibodies to ß₂ Glycoprotein I in human serum."
Therefore, the table below reflects the reported performance without specific pre-stated acceptance criteria being identified:
| Performance Metric | Reported Performance (VIRGO® β₂ Glycoprotein I IgM Antibody Kit) |
|---|---|
| Precision | |
| Inter-Assay % C.V. (Range) | 2.3% - 13.9% (for various samples and calibrator dilutions) |
| Intra-Assay % C.V. (Range) | 8.2% - 10.7% (for various samples) |
| Clinical Performance | |
| Relative Sensitivity | 87.9% (95% CI: 79.6% to 93.1%) compared to aCL IgM |
| Relative Specificity | 96.5% (95% CI: 90.4% to 98.8%) compared to aCL IgM |
| Relative Agreement | 93.3% (95% CI: 86.2% to 96.9%) compared to aCL IgM |
| Prevalence in APS1 | 62.8% (43 samples) |
| Prevalence in SLE + APS | 57.1% (7 samples) |
| Prevalence in RA | 0% (40 samples) |
| Prevalence in SLE (No APS) | 5.0% (20 samples) |
| Prevalence in Scl-70 | 0% (20 samples) |
| Prevalence in Infectious | 2.5% (40 samples) |
| Prevalence in Normals | 0% (120 samples) |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Performance Testing (Clinically Characterized Serum Samples):
- APS1: 43 samples
- SLE + APS: 7 samples
- Rheumatoid Arthritis: 40 samples
- SLE (No APS): 20 samples
- Scl-70 (No APS): 20 samples
- Infectious: 40 samples
- Normals: 120 samples
- Total for this section: 290 samples
- Sample Size for Comparison with aCL IgM:
- Clinically characterized APS serum samples: 50 samples
- Apparently healthy donors: 40 samples
- Total for this section: 90 samples
- Data Provenance: The document does not explicitly state the country of origin. It describes the data as "clinically characterized serum samples" and samples from "individuals diagnosed with Primary APS and other diseases." This indicates the data is retrospective as samples were already characterized.
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 for the test set. It only states that the samples were "clinically characterized" and from "individuals diagnosed" with specific conditions.
4. Adjudication Method for the Test Set
The document does not describe any adjudication method for the test set. The ground truth seems to be based on prior clinical diagnosis.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, an MRMC comparative effectiveness study was not done. This device is an in-vitro diagnostic (ELISA) kit and thus does not involve human readers interpreting images or data to the same extent as an AI device. The comparison was with another diagnostic test (aCL IgM).
6. If a Standalone Performance Study was Done
Yes, a standalone performance study was done. The precision studies (inter and intra-assay) and clinical performance testing against various patient groups (APS, SLE, RA, etc.) demonstrate the standalone performance of the VIRGO® β₂ Glycoprotein I IgM Antibody Kit. The "Comparison with aCL IgM" section also evaluates the device's performance in relation to a predicate, which can be seen as a form of standalone evaluation against established diagnostic methods.
7. The Type of Ground Truth Used
The ground truth used was clinical diagnosis and characterization of serum specimens. The samples were described as "clinically characterized serum samples" and from "individuals diagnosed with Primary APS and other diseases." For the comparison with aCL IgM, the ground truth for "APS" was based on clinical characterization, and "healthy donors" for the negative group.
8. The Sample Size for the Training Set
The document does not provide information regarding a separate training set. For in-vitro diagnostic kits like this, the development process typically involves internal validation and optimization, but a distinct "training set" for an AI algorithm is not applicable here. The performance data presented is generally for validation purposes.
9. How the Ground Truth for the Training Set Was Established
As there is no explicit training set discussed in the context of an AI algorithm, the method for establishing ground truth for a training set is not applicable or described in this document. The development of such ELISA kits relies on standardizing reagents and methods, and validating performance against clinically defined samples.
§ 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).