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The Access Thyroglobulin Antibody II 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 Thyroqlobulin Antibody II 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 Thyroglobulin Antibody II assay is a sequential two-step immunoenzymatic ("sandwich") assay. A sample is added to a reaction vessel with paramagnetic particles coated with the thyroglobulin protein. The TgAb in the sample binds to the thyroglobulin coated on the particles. After incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. The thyroglobulin-alkaline phosphatase conjugate is added and binds to the TgAb.

After second incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of analyte in the sample. Analyte concentration is automatically determined from a stored calibration.

Here's a detailed breakdown of the acceptance criteria and study information for the Beckman Coulter Access Thyroglobulin Antibody II device, extracted from the provided FDA 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The primary goal of this submission (K240996) is to demonstrate substantial equivalence of the same device on a new instrument platform (Dxl 9000 Access Immunoassay Analyzer) compared to its predicate on the Access 2 Immunoassay System. Therefore, the "acceptance criteria" are largely derived from the established performance of the predicate device.

2. Sample Sizes Used for the Test Set and Data Provenance

• Method Comparison Study (CLSI EP09c):
  • Sample Size: N = 114
  • Data Provenance: Not explicitly stated (e.g., country of origin, retrospective/prospective). However, such studies typically use clinical samples that may be either retrospectively collected or prospectively collected for validation purposes.
• Imprecision Study (CLSI EP05-A3):
  • Sample Size: 3 distinct "Samples" (concentrations) were tested. Each sample was tested 80 times (duplicate R.L per day for a minimum of 20 days).
  • Data Provenance: Not explicitly stated. Assumed to be laboratory samples or controls prepared for method validation.
• Reproducibility Study (CLSI EP05-A3):
  • Sample Size: 5 distinct "Samples" (concentrations) were tested. Each sample was tested 75 times (replicates of 5 per day for a minimum of 5 days on 3 instruments).
  • Data Provenance: Not explicitly stated. Assumed to be laboratory samples or controls prepared for method validation.
• Detection Capability (LoB, LoD, LoQ) Study (CLSI EP17-A2):
  • Sample Size: Not explicitly stated for each determination, but these studies typically involve multiple replicates of blank, low-level, and higher-level samples.
  • Data Provenance: Not explicitly stated. Assumed to be laboratory samples or controls.

3. Number of Experts Used to Establish Ground Truth and Qualifications

This document describes a clinical laboratory device (an immunoassay), not an AI/imaging device requiring expert interpretation of results for ground truth. Therefore, the concepts of "experts to establish ground truth" (in the context of clinical interpretation or diagnosis from an image) and their "qualifications" are not applicable here.

For this type of device, ground truth is established through:

• Reference Methods / Predicate Devices: The Access 2 Immunoassay System (predicate) served as the comparator for the method comparison study to assess the "truth" of the Dxl 9000 system's measurements.
• Certified Reference Materials/Standards: Calibrators and controls with known analyte concentrations, often traceable to international standards, are used to establish accuracy and calibration.
• Clinical Diagnosis: For the "Indications for Use," the device aids in diagnosis, meaning its results are interpreted by clinicians in conjunction with other clinical information. The diagnostic accuracy studies (sensitivity, specificity) in relation to a "gold standard" clinical diagnosis are typically part of a larger clinical trial not detailed in this specific 510(k) summary for a platform change.

4. Adjudication Method for the Test Set

Not applicable. As this is an immunoassay device assessing quantitative levels of an antibody, there is no "adjudication method" in the sense of reconciling divergent expert interpretations of qualitative or semi-quantitative data. The "test set" results—the quantitative values—are compared statistically to the reference method (predicate device) and assessed against performance specifications (imprecision, linearity, detection limits).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study was not done. This type of study is relevant for AI/imaging devices where multiple human readers interpret complex cases (e.g., medical images) and AI assistance might improve their performance. This document is for a medical laboratory immunoassay for quantitative measurement of thyroglobulin antibody, not an AI-assisted diagnostic tool for human interpretation.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

While the device operates "standalone" in the sense that the instrument performs the assay and generates a quantitative result without human intervention during the analytical process, this is not an "algorithm-only" study in the context of AI. The performance studies (imprecision, linearity, method comparison, detection capability) represent the standalone analytical performance of the instrument/reagent system. The "human-in-the-loop" would be the clinician interpreting the numerical result in the context of a patient's overall clinical picture, but the device itself functions automatically.

7. The Type of Ground Truth Used

• Quantitative Reference Values: For the performance studies, the ground truth is established through various means:
  • Method Comparison: The results obtained from the predicate device (Access Thyroglobulin Antibody II on the Access 2 Immunoassay System) serve as the reference standard.
  • Imprecision & Reproducibility: Derived from repeated measurements of samples (often control materials or pooled patient samples) to assess variability. The "true" value for these samples is either assigned by the manufacturer or determined through extensive testing.
  • Linearity: Determined by creating serially diluted samples from a high-concentration sample, where the expected concentration of each dilution is the "ground truth."
  • Detection Capability (LoB, LoD, LoQ): Established using blank samples and low-concentration spiked samples, with statistical methods determining the lowest detectable/quantifiable levels.

8. The Sample Size for the Training Set

This document does not describe a machine learning or AI algorithm development that would typically involve a "training set." The studies described are for analytical validation of an immunoassay on a new instrument platform, focusing on demonstrating equivalent performance to a predicate device. Therefore, a "training set" in the AI sense is not applicable.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as there is no "training set" in the context of AI or machine learning for this immunoassay device.

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