(55 days)
ACE® T4 Reagent is intended for use in the quantitative determination of thyroxine in human serum.
ACE® T4 Reagent is used in the diagnosis and treatment of thyroid disorders. It is intended for the quantitative determination of thyroxine in serum using the ACE clinical chemistry analyzer.
The ACE® T4 Reagent contains two reagents, an Antibody/Substrate reagent and an Enzyme Coniugate reagent. The assay uses 8-anilino-1-naphthalene sulfonic acid (ANS) to dissociate thyroxine from the plasma-binding proteins. The dissociated thyroxine in the sample competes with an enzyme glucose-6-phosphate dehydrogenase (G6PDH) labeled thyroxine for a fixed amount of anti-thyroxine specific antibody binding sites. In the absence of thyroxine from the sample, the thyroxine-labeled G6PDH is bound by the specific antibody and the enzyme activity is inhibited. This phenomenon creates a relationship between thyroxine concentration in the sample and the enzyme activity. The enzyme G6PDH activity is determined bichromatically on the ACE® at 340/505 nm by measuring its ability to convert NAD* to NADH.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the ACE® T4 Reagent are implicitly defined by its substantial equivalence to the predicate device, the DRI Thyroxine (T4) Enzyme Immunoassay. The reported device performance is compared directly to the predicate device's performance characteristics.
| Parameter | Acceptance Criteria (Predicate Device) | Reported Device Performance (ACE® T4 Reagent) |
|---|---|---|
| Assay Range | 0.7 µg/dL to 20 µg/dL | 0.47 µg/dL to 20 µg/dL |
| Precision | ||
| - Within Run | 5.4 %CV | 3.7 %CV |
| - Between Run | 4.3 %CV | 4.6 %CV |
| Correlation vs | Commercial thyroxine assay | Hitachi 717 |
| - Slope | 1.02 | 1.070 |
| - Intercept | -0.63 | -0.405 |
| - r | 0.993 | 0.9824 |
| - N | 108 | 50 |
2. Sample Size Used for the Test Set and Data Provenance
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Test Set Sample Size (Correlation Study):
- Predicate Device: 108 samples (N=108)
- Proposed Device: 50 samples (N=50)
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Data Provenance: The document does not explicitly state the country of origin or whether the data was retrospective or prospective. Given the context of a 510(k) submission for an in-vitro diagnostic, it is generally assumed to be prospective clinical studies or laboratory studies conducted in a controlled environment as part of performance validation.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This document describes an in-vitro diagnostic (IVD) device for quantitative determination of thyroxine in human serum. For such devices, "ground truth" is typically established by reference methods or validated comparative assays, rather than expert consensus on images or clinical assessments. The comparison is made against existing commercial thyroxine assays (for the predicate) and the Hitachi 717 analyzer (for the proposed device). Therefore, the concept of "experts" to establish ground truth as would be relevant for image-based diagnostic aids does not directly apply here. The expertise lies in the established accuracy and reliability of the comparative analytical methods.
4. Adjudication Method for the Test Set
Not applicable. As described in point 3, the ground truth is established by comparative analytical methods, not by human adjudication of observations.
5. 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 in-vitro diagnostic reagent, not an imaging device or an AI-assisted diagnostic tool that would involve human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, this is effectively a standalone performance study. The device (ACE® T4 Reagent) is an analytical tool that quantitatively determines thyroxine levels. Its performance (precision and correlation) is evaluated directly, without human interpretation of results as part of the primary measurement.
7. The Type of Ground Truth Used
The ground truth for the test set (correlation study) was established by:
- For the predicate device: A "Commercial thyroxine assay."
- For the proposed device: The "Hitachi 717" analyzer, which itself is a widely accepted clinical chemistry analyzer.
This is a form of comparative assay reference method or reference instrument data used to establish equivalency and accuracy for IVDs.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning, as this device is a reagent for an enzyme immunoassay, not an AI software. The performance assessment section focuses on validation data (precision and correlation).
For traditional IVDs, "training" might refer to the development and optimization of the assay itself using various samples, but specific sample sizes for such a "training set" are not typically reported in 510(k) summaries in this manner, nor are they relevant in the same way as for AI/ML models.
9. How the Ground Truth for the Training Set Was Established
Not applicable in the context of machine learning. The "ground truth" for developing a chemical assay typically involves using calibrators and control materials with known concentrations, or comparing against established reference methods during the assay development phase. These details are not provided in this 510(k) summary.
§ 862.1700 Total thyroxine test system.
(a)
Identification. A total thyroxine test system is a device intended to measure total (free and protein bound) thyroxine (thyroid hormone) in serum and plasma. Measurements obtained by this device are used in the diagnosis and treatment of thyroid diseases.(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9.