(38 days)
The Access Thyroglobulin Antibody II (TgAb) assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of thyroglobulin antibody levels in human serum and plasma using the Access Immunoassay Systems. The measurement of thyroid autoantibodies may aid in the diagnosis of Hashimoto's disease, nontoxic goiter, and Graves' disease.
The Access Thryoglobulin Antibody II reagents, calibrators, and the Access Immunoassay Analyzers (Access, Access 2, Synchron LXi 725, UniCel DxC 600i, and UniCel DxI 800) comprise the Access Immunoassay Systems for the determination of thyroglobulin antibody (TgAb) levels in human serum and plasma.
Here's a breakdown of the acceptance criteria and study information for the Access Thyroglobulin Antibody II Assay, based on the provided 510(k) summary:
Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Imprecision | |
| Within-run CV | 4.0% CV to 5.8% CV |
| Between-run CV | 2.7% CV to 5.1% CV |
| Total Imprecision | 4.8% CV to 7.0% CV |
| Low Dose Imprecision (SD) | 0.3 to 0.8 SD |
| Dilution Recovery (Linearity) | Mean % recovery ranged from 118% to 127% |
| Analytical Sensitivity (Lowest detectable level distinguishable from zero with 95% confidence) | 0.9 IU/mL |
| Methods Comparison | |
| Positive % Agreement with predicate device | 95% |
| Negative % Agreement with predicate device | 99.6% |
| Overall Percent Agreement with predicate device | 99% |
| Analytical Specificity (No significant interference from potential sample contaminants) | No significant interference from bilirubin, hemoglobin, human serum albumin, triglycerides, and autoantibodies. |
| Expected Values (95% non-parametric upper reference limit in normal population) | Below 4 IU/mL (137 screened samples) and 96% of 519 normal samples below 4 IU/mL |
Study Details:
-
Sample size used for the test set and the data provenance:
- Methods Comparison: 832 values were used for comparison. The document does not explicitly state the country of origin, but given the applicant is in the US and the clinical studies for expected values were in the US, it is highly likely this data is from the United States. The study appears to be retrospective as it compares the new device with a "commercially available enzyme immunoassay kit" which implies existing samples.
- Imprecision, Dilution Recovery, Analytical Sensitivity, Analytical Specificity: Sample sizes are not explicitly given for each of these analytical studies, but details like "multiple dilutions," "20 replicates of the zero calibrator," and "sera samples obtained in the United States" are mentioned. For Expected Values, 137 screened samples and an additional 519 normal samples were collected in the United States. These appear to be prospective collections based on specific screening criteria.
-
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This device is an immunoassay for quantitative determination of antibody levels. The "ground truth" for the analytical studies (imprecision, linearity, sensitivity, specificity) is based on the inherent properties of the assay and reference materials, not expert interpretation.
- For the Methods Comparison, the "ground truth" was established by a "commercially available enzyme immunoassay kit." This implicitly means the established performance of that predicate device determined the reference. No human experts are mentioned for establishing ground truth in this context.
- For Expected Values, the "ground truth" for "normal" was defined by specific clinical criteria (serum TSH levels, no personal/family history of thyroid disease, absence of non-thyroid autoimmune disease). This relies on clinical diagnosis and laboratory results rather than expert consensus on individual cases for the test set.
-
Adjudication method for the test set:
- Not applicable as this is an immunoassay device, and the "ground truth" in the analytical studies is based on established laboratory methods, reference ranges, or a comparator device's results, not on expert adjudication of individual case results.
-
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:
- Not applicable. This device is an in vitro diagnostic (IVD) immunoassay for quantitative measurement, not an AI-assisted diagnostic imaging or interpretation device that would involve human readers.
-
If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, the performance characteristics (imprecision, dilution recovery, analytical sensitivity, analytical specificity, methods comparison) reflect the standalone performance of the Access Thyroglobulin Antibody II Assay as an automated immunoassay system. There is no human-in-the-loop component described for its primary function of quantitative determination.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For analytical studies:
- Imprecision, Dilution Recovery, Analytical Sensitivity, Analytical Specificity: Ground truth is based on the intrinsic properties of the assay system, known standards, and controlled experimental conditions typical for IVD assay validation.
- Methods Comparison: Ground truth was established by the results from a commercially available enzyme immunoassay kit (the predicate device).
- For clinical studies (Expected Values): Ground truth for "normal" was established by clinical criteria (TSH levels, medical history) rather than a single type of definitive outcome or pathology for each individual.
- For analytical studies:
-
The sample size for the training set:
- The document describes the validation of the device, not the development of an algorithm that requires a "training set." This is an immunoassay, not a machine learning model. Therefore, the concept of a training set in the AI/ML sense is not applicable. The studies described are for validation of the assay's performance.
-
How the ground truth for the training set was established:
- Not applicable, as there is no "training set" in the context of this immunoassay.
§ 866.5870 Thyroid autoantibody immunological test system.
(a)
Identification. A thyroid autoantibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the thyroid autoantibodies (antibodies produced against the body's own tissues). Measurement of thyroid autoantibodies may aid in the diagnosis of certain thyroid disorders, such as Hashimoto's disease (chronic lymphocytic thyroiditis), nontoxic goiter (enlargement of thyroid gland), Grave's disease (enlargement of the thyroid gland with protrusion of the eyeballs), and cancer of the thyroid.(b)
Classification. Class II (performance standards).