(45 days)
The quantitative determination of thyroglobulin autoantibodies in human serum or plasma by a microplate enzymeimmunoassay. Measurements of Tg autoantibodies may aid in the diagnosis of certain thyroid diseases such as Hashimoto, Graves, and nontoxic goiter.
The Monobind method is based on ELISA technology utilizing the streptavidin-blotin reaction to effect separation. Upon mixing blotinylated thyroglobulin antigen, and a serum containing the autoantibody (anti-Tg), reaction results between the biotinylated thyroglobulin antigen and the antibodies to form an immune complex. Simultaneously, the complex is deposited to the well through the high affinity reaction of streptavidin, coated on the well, and biotinylated thyroglobulin antigen. After incubation is complete, decantation or aspiration separates the unbound components. The enzyme linked species specific antibody (anti-h-igG) is then added to the microwells. The anti-h-lgG enzyme conjugate that binds to the immobilized immune complex in a second incubation are separated from unreacted material by a wash step. The enzyme activity in this fraction Is directly proportional to the antibody concentration in the specimen. By utilizing several different serum references of known antibody activity, a reference curve can be generated from which the antibody activity of an unknown can be ascertained.
Here's a breakdown of the acceptance criteria and the study details for the Monobind Anti-Thyroglobulin (Tg) Microplate ELISA, based on the provided text:
Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Clinical Comparison (method agreement with predicate device) | Linear regression: 0.995 correlation coefficient |
| Equation: y = 9.79 + 0.969(x) | |
| Mean values: Reference method: 419.2 IU/ml; This method: 415.6 IU/ml | |
| Linearity of Dilutions (Recovery) | Average 98.7% recovery |
Study Details
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Sample size used for the test set and the data provenance:
- Sample Size: 82 biological specimens.
- Data Provenance: The specimens were from "normal and disease states populations," including "Hashimoto's thyroiditis, Graves Disease, thyroid nodules as well as thyroid carcinoma." The text does not specify the country of origin, but it implies human serum or plasma samples. The study appears to be retrospective as it used existing biological specimens for comparison.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not explicitly state the number of experts or their qualifications. The "ground truth" for the test set appears to be established by the "reference method" (the Biomerica anti-thyroglobulin ELISA test), which is itself a validated diagnostic method. The values for comparison were "known antibody activity," implying established measurements from the predicate device.
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Adjudication method for the test set:
- The document does not describe an adjudication method involving experts. The comparison was quantitative, based on linear regression between the new device's measurements and the predicate device's measurements.
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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:
- No, an MRMC comparative effectiveness study was not done. This device is an ELISA kit, which is an in-vitro diagnostic test, not an AI-assisted imaging or diagnostic tool that would involve human readers in the classical sense.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, this study represents a standalone performance evaluation of the ELISA kit. The "algorithm" here is the chemical reaction and measurement process of the ELISA kit itself, without direct human interpretation influencing the numerical result.
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The type of ground truth used:
- The primary ground truth used for performance comparison was the quantitative results obtained from a predicate device (Biomerica anti-thyroglobulin ELISA test), which is itself a legally marketed diagnostic method. This is a form of clinical comparison against an established method. The results were also tied to "known antibody activity" and specimens from "disease states," implying a correlation with clinical diagnoses.
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The sample size for the training set:
- The document does not specify a separate "training set" in the context of device development. For an ELISA kit, method development (e.g., optimizing reagent concentrations) would involve internal testing, but the 82 specimens discussed are for the validation/test set used to demonstrate substantial equivalence.
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How the ground truth for the training set was established:
- As there's no explicitly mentioned "training set" with ground truth establishment described for this type of device, this question is not directly applicable in the context of the provided information. Instead, the "ground truth" for calibrators (standards) used in the assay itself is established by preparing them from "diluted human serum" "standardized against the same international reference material 1st IRP 65/93." This ensures the traceability and accuracy of the calibration curve.
§ 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).