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The ARCHITECT Free T4 (FT4) assay is a Chemiluminescent Microparticle Immunoassay (CMIA) for the quantitative determination of free thyroxine (Free T4) in human serum and plasma.

ARCHITECT Free T4 (FT4) assay is to be used as an aid in the assessment of thyroid status.

The ARCHITECT Free T4 assay is a two-step immunoassay for the quantitative determination of free thyroxine (Free T4) in human serum and plasma using CMIA technology with flexible assay protocols, referred to as Chemiflex.

In the first step, sample and anti-T4 coated paramagnetic microparticles are combined. Free T4 (unbound) present in the sample binds to the anti-T4 coated microparticles. After washing, Ts acridinium-labeled conjugate is added to create a reaction mixture. Following another wash cycle, pre-trigger and trigger solutions are added to the reaction mixture. The resulting chemiluminescent reaction is measured as relative light units (RLUs). An inverse relationship exists between the amount of Free T4 in the sample and the RLUs detected by the ARCHITECT i System optics.

The provided text describes a 510(k) premarket notification for a modification to the ARCHITECT Free T4 assay, not a study proving device meets acceptance criteria in the context of AI/ML or comparative effectiveness. The device is an in-vitro diagnostic (IVD) test, and the information requested about AI/ML models, human readers, and ground truth types (pathology, outcomes data) is not applicable to this type of device or documentation.

However, I can extract the acceptance criteria and performance data related to the nonclinical performance verification for the modified ARCHITECT Free T4 assay, as presented in the document.

Acceptance Criteria and Reported Device Performance

The device under review is an in-vitro diagnostic (IVD) assay, not an AI/ML device. Therefore, acceptance criteria and performance are based on analytical performance studies. The document states that the "device passed all of the tests based on pre-determined acceptance criteria." While the specific numerical acceptance criteria are not detailed in this summary, the types of tests performed and the general outcome are reported.

1. Sample sized used for the test set and the data provenance:

The document does not specify the exact sample sizes used for each individual nonclinical performance study (Limit of Blank/Detection/Quantitation, Precision, Accuracy, Stability, Linearity). It also does not explicitly state the country of origin of the samples or if they were retrospective or prospective, though for IVD analytical performance, these would typically be control samples and patient samples collected for various analytical evaluations to represent the intended use population.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

Not applicable. For an immunoassay, the "ground truth" for analytical performance studies is established by the assay's ability to accurately and precisely measure the analyte (Free T4) in samples against known concentrations or reference methods, not by expert interpretation of images or clinical data.

3. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

Not applicable. Adjudication methods like 2+1 are used for expert consensus on subjective interpretations (e.g., radiology reads), which is not relevant for an IVD analytical performance study.

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 is an IVD assay, not an AI/ML diagnostic tool involving human readers.

5. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

Not applicable. This is an IVD immunoassay, not an algorithm or AI model. Its performance is inherent to the assay chemistry and instrument.

6. The type of ground truth used:

For the analytical performance studies, the "ground truth" is established through:

• Known concentrations: For studies like linearity, limits, and precision, samples with known concentrations of Free T4 would be used.
• Reference methods/comparative methods: For accuracy by correlation, the results of the ARCHITECT Free T4 assay would be compared against a legally marketed predicate device (as referenced, K123379) or a recognized reference method.

7. The sample size for the training set:

Not applicable. This is an immunoassay, not an AI/ML model, so there is no "training set" in the computational sense. The development of the assay reagents and protocols is based on chemical and biological research and optimization.

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

Not applicable, as there is no "training set" in the context of an AI/ML model. The development of the assay components (reagents, microparticles, conjugate) and the associated manufacturing process enhancement (reduced microparticle percent solids) are validated through the nonclinical performance studies listed.

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The ARCHITECT Free T4 (FT4) assay is a Chemiluminescent Microparticle Immunoassay (CMIA) for the quantitative determination of free thyroxine (Free T4) in human serum and plasma. The ARCHITECT Free T4 assay is to be used as an aid in the assessment of thyroid status.

The ARCHITECT Free T4 Calibrators are for the calibration of the ARCHITECT i System when used for the quantitative determination of free thyroxine (Free T4) in human serum and plasma when using the ARCHITECT Free T4 Reagent Kit.

The ARCHITECT Free T4 Controls are for the verification of the accuracy and precision of the ARCHITECT i System when used for the quantitative determination of free thyroxine (Free T4) in human serum and plasma when using the ARCHITECT Free T4 Reagent Kit.

The ARCHITECT Free T4 assay is a two-step immunoassay to determine the presence of free thyroxine (Free T4) in human serum and plasma using CMIA technology with flexible assay protocols, referred to as Chemiflex.

In the first step, sample and anti-T4 coated paramagnetic microparticles are combined. Free T 4 (unbound) present in the sample binds to the anti-T4 coated microparticles. After washing. T3 acridinium labeled conjugate is added in the second step. Pre-Trigger and Trigger Solutions are then added to the reaction mixture; the resulting chemiluminescent reaction is measured as relative light units (RLUs). An inverse relationship exists between the amount of Free T4 in the sample and the RLUs detected by the ARCHITECT i optical system.

The calibrators are devices intended for medical purposes for use in the ARCHITECT Free T 4 assay test system to establish points of reference that are used in the quantitative determination of values in the measurement of substances in human specimens. Free T4 measurements are used as an aid in the assessment of thyroid status.

This is a 510(k) summary for a medical device modification, specifically for the Abbott ARCHITECT Free T4 assay. It describes the device, its intended use, and the modifications made. The document also lists the verification and validation studies performed to demonstrate the device's performance after the modification. However, the provided text does not contain explicit "acceptance criteria" for the device's overall performance, nor does it present a study that directly "proves" the device meets such criteria in the format requested.

Instead, the document focuses on demonstrating substantial equivalence to a predicate device after a modification (changing from a 2-point to a 6-point calibration). The studies listed are typical for verifying the analytical performance of an in vitro diagnostic (IVD) device after a change, ensuring that the modified device performs comparably or better and continues to be safe and effective for its intended use.

Here's an attempt to extract the requested information based on the provided text, acknowledging that many details are not explicitly stated in the typical format of acceptance criteria and performance results:

1. Table of Acceptance Criteria and Reported Device Performance

As the document is a 510(k) summary for a modification, it describes studies conducted to demonstrate that the modified device is substantially equivalent to the predicate. Explicit, consolidated acceptance criteria with directly corresponding performance results in a single table are not provided. Instead, the document lists specific studies (e.g., Accuracy by Correlation, Limits of Blank/Detection/Quantitation, Linearity, Precision) that would have had their own internal acceptance criteria for passing.

For instance, the "Limits of Blank/Detection/Quantitation (LoB/LoD/LoQ)" are presented as device specifications, which could imply internal acceptance criteria were met during their determination.

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

The document lists various verification/validation studies, but does not specify the sample sizes used for these studies. It refers to human serum and plasma being used for the determination of Free T4, implying human samples. The provenance of the data (e.g., country of origin, retrospective or prospective) is not mentioned.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not applicable or provided in this type of document. For an in vitro diagnostic assay like Free T4, the "ground truth" for the test set values is typically established by reference methods, gravimetric methods, or highly characterized reference materials, not by expert human graders or reviewers in the way an imaging AI algorithm might use. The calibrators described are matched to an "Abbott internal reference standard" manufactured by gravimetric methods, which serves as a form of ground truth for calibration.

4. Adjudication Method for the Test Set

This is not applicable for this type of IVD device and its verification studies. Adjudication methods (like 2+1, 3+1) are typically used in clinical trials or studies where human expert consensus is needed to determine the "correct" classification or diagnosis, often in imaging or pathology. For an analytical assay, the "correct" value is determined instrumentally or by reference methods.

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

No, an MRMC comparative effectiveness study was not done. This type of study is relevant for AI algorithms that assist human readers (e.g., radiologists interpreting images) to quantify the improvement in human performance with AI assistance. The ARCHITECT Free T4 assay is an automated in vitro diagnostic test system, not an AI-assisted human reading device.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

The device itself is a standalone automated diagnostic assay. The listed studies (Accuracy, Limits, Linearity, Precision) are all demonstrations of the algorithm/system's standalone performance in determining Free T4 levels. There is no human-in-the-loop component for the measurement process itself, beyond operating the instrument and interpreting the numerical result.

7. The Type of Ground Truth Used

The ground truth for the device's calibration and analytical performance is established through:

• Abbott internal reference standard, which is manufactured by gravimetric methods based on Free Thyroxine calculation (FT4c) using L-Thyroxine, sodium salt pentahydrate (HPLC grade).
• For precision studies, "native samples" (real patient samples) are mentioned, which would presumably be analyzed against the established calibration curve.
• "Accuracy by Correlation" implies comparison to a reference method or the predicate device, which would serve as a comparative ground truth.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of an AI algorithm. For an IVD assay, the system is "trained" by calibrators. The modified device uses a 6-point calibration (levels: 0.0, 0.5, 1.0, 2.0, 3.5, 6.0 ng/dL L-thyroxine in human serum). The number of runs or replicates used to establish the calibration curve from these 6 points is not specified.

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

The "ground truth" for the calibrators (which serve as the "training set" for the instrument's measurement curve) is established by:

• Gravimetric methods using L-Thyroxine, sodium salt pentahydrate (HPLC grade) to prepare the calibrators at specific, known concentrations.
• These calibrators are further "matched to an Abbott internal reference standard," which itself is manufactured and characterized by gravimetric methods. This ensures traceability and accuracy of the calibrator values.

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The ARCHITECT™ Free T (FT) assay is a Chemiluminescent Microparticle Immunoassay (CMIA) for the quantitative determination of free thyroxine (free T ) in human serum and plasma. The ARCHITECT Free T assay is to be used as an aid in the assessment of thyroid status.

ARCHITECT Free T, is a Chemiluminescent Microparticle Immunoassay (CMIA) for the quantitative determination of free T, in human serum or plasma (lithium heparin, sodium heparin or potassium EDTA). ARCHITECT Free T, is calibrated with ARCHITECT Free T. Calibrators. ARCHITECT Free T. Controls are assaved for the verification of the accuracy and precision of the Abbott ARCHITECT i System.

Here's an analysis of the provided 510(k) summary regarding the Abbott ARCHITECT™ Free T4 assay, structured to address your specific questions.

It's important to note that the provided document is a 510(k) summary, which is a high-level overview. Detailed study protocols and full results are typically found in the complete 510(k) submission, which is not included here. Therefore, some information might be missing or inferred based on common practices for such submissions.

Acceptance Criteria and Study Details for Abbott ARCHITECT™ Free T4

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary focuses on demonstrating substantial equivalence to a predicate device rather than defining explicit performance acceptance criteria in the way one might for a novel classification. For substantial equivalence, the key acceptance criteria revolve around showing comparable analytical performance.

Interpretation: The reported performance metrics (high correlation, slopes close to 1, and intercepts close to 0, especially with Passing-Bablok) indicate a strong agreement between the new ARCHITECT™ Free T4 assay and the predicate AxSYM® Free T4 assay, signifying comparable analytical performance.

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

• Sample Size: 1250 specimens
• Data Provenance: Not explicitly stated in the provided summary (e.g., country of origin, specific demographics). It is listed as "human serum or plasma."
• Retrospective or Prospective: Not explicitly stated. For a 510(k) submission comparing a new device to a predicate, it is common to use retrospectively collected samples, or a mix, to cover a broad range of clinically relevant analyte concentrations.

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

This information is not applicable and therefore not provided in the 510(k) summary for this type of device and study.

For assays like this, which measure an analyte quantitatively, the "ground truth" for the test set is established by running the samples on the predicate device (AxSYM® Free T4 assay). The AxSYM® Free T4 assay itself serves as the reference against which the new ARCHITECT™ Free T4 assay is compared. There isn't typically a need for human experts to establish ground truth in the same way they would for image interpretation or disease diagnosis.

4. Adjudication Method for the Test Set

This information is not applicable for this type of study. Adjudication methods (like 2+1, 3+1) are typically used when there is subjective interpretation involved, such as in clinical trials or image analysis where multiple readers might disagree. For quantitative assays comparing a new device to a predicate, the results from the predicate device serve as the direct comparator, and no human adjudication of results is described or necessary.

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

An MRMC study was not conducted and is not applicable for this type of in vitro diagnostic device (IVD). MRMC studies are primarily used for diagnostic imaging devices or other human-interpreted diagnostics to assess the impact of AI assistance on human reader performance. This submission is for a quantitative chemical assay.

6. Standalone (Algorithm Only) Performance

The study implicitly represents standalone performance in the context of an IVD. The ARCHITECT™ Free T4 assay (the "algorithm" or device under review) was run on its own, and its results were directly compared to the predicate device. There is no "human-in-the-loop" component in the operation of this automated assay itself.

7. Type of Ground Truth Used

The "ground truth" used for comparison was the results obtained from the predicate device, the AxSYM® Free T4 assay. This is a comparative analytical performance study where the well-established predicate serves as the reference standard.

8. Sample Size for the Training Set

This information is not provided in the summary. For IVDs, "training sets" are distinct from "test sets" and might refer to samples used during the development and calibration of the assay. The 1250 specimens mentioned are specifically for the comparison (test) phase. The summary does state the ARCHITECT Free T4 is "calibrated with ARCHITECT Free T. Calibrators" but does not give sample sizes for this calibration process.

9. How Ground Truth for the Training Set Was Established

This information is not provided in the summary. For the development and calibration of the assay (what might be considered "training"), ground truth would typically be established using:

• Reference materials/standards: Traceable to international or national standards for free T4.
• Highly characterized samples: Often involving methods with higher analytical rigor (e.g., mass spectrometry) if available and necessary to establish target values for calibrators.
• Consensus values: For in-house calibrators, a set of highly reliable measurements from multiple runs on the developed assay and/or comparison to established reference methods could be used.

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