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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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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 goter, 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 consists of the reagent pack and calibrators. Other items needed to run the assay include substrate and wash buffers. The assay is run on Access 2 Immunoassay Analyzers.

The device modifications described in this submission impact the Access Thyroqlobulin Antibody II reagent pack only; they do not impact or change the other components that are used with this reagent pack. The modification does not affect the intended use or indications of the device or alter the fundamental scientific technology of the device.

A description of the reagent pack is provided below.

Here's an analysis of the provided text, outlining the acceptance criteria and study details for the "Access Thyroglobulin Antibody II" device:

Device: Access Thyroglobulin Antibody II

The study in the document focuses on the modified Access Thyroglobulin Antibody II assay and compares it to the previously cleared predicate device (Access Thyroglobulin Antibody II Assay, FDA 510(k) Number K112933). The goal is to demonstrate substantial equivalence of the modified device.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present acceptance criteria in a dedicated table format. Instead, it describes performance characteristics and the results obtained. I've reconstructed a table based on the implicit criteria derived from the reported performance, especially where a target value or range is given (e.g., for imprecision, biases, or correlation).

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

• Method Comparison: n = 123 samples. Data provenance not specified (country of origin, retrospective/prospective).
• Imprecision: Not specified, but involved reagent lots and instrument details suggest laboratory testing.
• Reproducibility: Not specified, but involved reagent lots and instrument details suggest laboratory testing.
• High-dose Hook Effect: Not specified how many samples were tested, but concentrations up to 50,000 IU/mL were used.
• Linearity: Not specified how many samples were tested, but both serum and plasma samples were used.
• Sensitivity (LoB, LoD, LoQ): Not specified how many samples were used, but involved 2 reagent lots and 2 instruments over a minimum of 3 days (LoB) or 5 days (LoD, LoQ).
• Analytical Specificity:
  • Cross-reactive disease states: "Samples with potential cross-reactive disease states were tested." Number of samples not specified.
  • Potential interferents: "Patient serum samples containing two levels of thyroglobulin antibody at clinically relevant concentrations of approximately 4 IU/mL and 100 IU/mL." Number of samples not specified, but specific interferents (like biotin at 3510 ng/mL) were tested.
• Matrix Comparison: Fifty (50) matched sets of serum, lithium heparin plasma, and EDTA plasma samples.

Data Provenance: The document does not specify the country of origin for any of the samples used in these studies, nor does it explicitly state if the studies were retrospective or prospective, though "patient samples" implies retrospective collection or prospective enrollment for the study.

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

This device is an in vitro diagnostic (IVD) immunoassay, not an imaging device typically requiring expert interpretation for ground truth. Therefore, the concept of "experts" establishing ground truth in the traditional sense of clinical diagnosis (e.g., radiologists, pathologists) does not directly apply here.

For IVDs, "ground truth" is typically established by:

• Reference methods/devices.
• Certified reference materials.
• Pathology or histopathology (for certain tests).
• Clinical outcomes/diagnosis (for certain tests).
• Known concentrations in spiked samples or characterized panels.

In this document:

• The "Method Comparison" used a "commercially available immunoassay" as a comparator, which serves as a de facto reference for comparison.
• Analytical specificity testing used "potential cross-reactive disease states" and "potential interferents" for which the expected results (presence/absence of Thyroglobulin Antibody, or known interference levels) would be pre-established or determined by a reference method.
• Sensitivity studies (LoB, LoD, LoQ) involve statistical calculations based on repeated measurements of samples with very low or zero analyte concentrations, not expert consensus.
• Concentration ranges for linearity were established using characterized samples.

Therefore, no information on human experts establishing ground truth is provided, as it's not relevant for this type of device validation.

4. Adjudication Method for the Test Set

Adjudication methods (like 2+1, 3+1) are typically used for studies where multiple human readers interpret medical images or complex data, and their interpretations need to be reconciled to establish a ground truth.

Since this is an in vitro diagnostic device measuring an analyte concentration, and the gold standard for comparison typically involves laboratory methods or reference materials, an adjudication method for a test set is not applicable or described in this document. The "ground truth" for the various performance characteristics is established by analytical methods and comparisons to reference standards or predicate devices.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This type of study is relevant for medical imaging devices where the performance of human readers, with and without AI assistance, is evaluated using a set of cases. This document describes an in vitro diagnostic device, an immunoassay, which does not involve human interpretation of images or complex data in a way that MRMC studies would be applicable.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, the studies described are all standalone performance evaluations of the Access Thyroglobulin Antibody II assay. This means the studies assess the device's ability to measure thyroglobulin antibody levels independent of human intervention in the interpretation of the result in the context of the device's analytical performance. The Access Immunoassay Systems are automated, and the assay's performance metrics (imprecision, linearity, sensitivity, specificity, etc.) are solely based on the analytical capabilities of the device itself.

7. The Type of Ground Truth Used

The type of "ground truth" used varies depending on the specific study:

• Method Comparison: A "commercially available immunoassay" served as the comparative standard. The results from this predicate/reference immunoassay formed the basis for comparing the new device's measurements.
• Imprecision & Reproducibility: Ground truth is implicit in the known characteristics of the control materials or spiked samples used, and the statistical variability observed from repeated measurements defines the performance.
• High-dose Hook Effect & Linearity: Ground truth is established by using samples with known or precisely characterized concentrations, often prepared by dilution or spiking.
• Sensitivity (LoB, LoD, LoQ): Statistical models are used based on repeated measurements of blank samples and samples with very low (but known) analyte concentrations.
• Analytical Specificity:
  • Cross-reactive disease states: Likely involved samples from patients with these conditions, where the presence/absence of TgAb would have been characterized by a reference method or clinical diagnosis. The "ground truth" then is the expected TgAb status based on the sample's origin.
  • Potential interferents: Involved adding known concentrations of interfering substances to samples with known TgAb concentrations. The "ground truth" is the expected TgAb concentration without interference.
• Matrix Comparison: Used matched samples from different matrices (serum, plasma), where the inherent TgAb concentration within a given patient sample is the ground truth against which each matrix measurement is compared.

In summary, the ground truth for this IVD device is primarily established through comparisons to established reference methods/predicate devices, known concentrations in characterized samples (spiked or diluted), and statistical analysis of performance with control materials.

8. The Sample Size for the Training Set

The document describes studies for validation of a modified device, demonstrating substantial equivalence to a predicate. It does not mention a "training set" in the context of developing an algorithm or AI model. This is an immunoassay, not a machine learning model that typically requires a large training dataset. The studies focus on analytical performance rather than diagnostic accuracy determined by a machine learning pipeline.

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

As noted above, there is no mention of a "training set" or "ground truth" established for training in this document, as the device is an immunoassay not based on a trainable algorithm.

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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

Study Details:

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. How the ground truth for the training set was established:

   • Not applicable, as there is no "training set" in the context of this immunoassay.

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