(55 days)
ACE T Uptake Reagent is used in the diagnosis and treatment of thyroid disorders. It is intended for the quantitative determination of unsaturated binding sites on the thyroid-binding proteins in serum using the ACE clinical chemistry analyzer.
The ACE T Uptake Regent contains two reagents, and Antibody/Substrate reagent and an Enzyme The assay uses a mixture of enzyme glucose-6-phosphate dehydrogenase Conjugate reagent. conjugated thyroxine (G6PD-T4) and a known amount of exogeneous T4 which is allowed to bind to the thyroxine-binding proteins in the sample. A sample with increased levels of unsaturated thyroxine-binding sites, the exogeneous T4 will bind leaving G6PD-T4 conjugate free. On addition of an anti-thyroxine antibody, the G6PD-T4 conjugate is bound by the antibody and the enzyme activity is inhibited. Conversely, a sample with decreased levels of unsaturated thyroxine-binding sites will leave most exogeneous T4 unbound. Upon addition of anti-T4 antibody, the unbound exogeneous T4 will inhibit the anti-T4 binding to G6PD-T4 conjugate and produce a high G6PD enzyme activity. This phenomenon creates a relationship between unsaturated thyroxine-binding sites concentration (T Uptake) and the enzyme activity. The enzyme G6PD activity is determined bichromatically on the ACE® at 340/505 nm by measuring its ability to convert NAD* to NADH.
Acceptance Criteria and Device Performance Study for ACE® T Uptake Reagent (K981375)
This document describes the acceptance criteria and a summary of the performance study for the ACE® T Uptake Reagent, based on the provided 510(k) premarket notification.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the ACE® T Uptake Reagent are implicitly defined by its substantial equivalence to the predicate device (Diagnostic Reagents, Inc. T Uptake Enzyme Immunoassay, K951586). The study aimed to demonstrate that the new device's performance characteristics are comparable to, or better than, the predicate device.
| Performance Characteristic | Acceptance Criteria (from Predicate Device) | Reported Device Performance (ACE® T Uptake Reagent) |
|---|---|---|
| Assay Range | 15% to 50% | 15% to 50% |
| Precision | ||
| Within Run (%CV) | 3.6% CV | 3.7% CV |
| Between Run (%CV) | 3.3% CV | 4.1% CV |
| Correlation vs. | Commercial EIA assay for FTI | Hitachi 717 Assay for T Uptake |
| Slope | 0.92 | 1.085 |
| Intercept | 0.69 | -3.460 |
| r (correlation coefficient) | 0.9 | 0.935 |
Note: The document explicitly states that "Based on these data, the Schiapparelli Biosystems ACE® T Uptake Reagent is substantially equivalent to the predicate device." This implies that meeting or closely matching the predicate's performance metrics served as the acceptance criteria.
2. Sample Size and Data Provenance for the Test Set
- Sample Size (for correlation study): N = 50
- Data Provenance: The document does not explicitly state the country of origin or whether the data was retrospective or prospective. However, given that this is a 510(k) submission for a diagnostic reagent, it is highly probable that the data was generated prospectively during a validation study conducted in a clinical laboratory setting, likely within the United States.
3. Number and Qualifications of Experts for Ground Truth
- Number of Experts: Not applicable. This type of device (reagent for quantitative determination) does not typically involve expert interpretation of results for establishing ground truth in the same way an imaging device might. The "ground truth" for the test set is established through comparison with a recognized reference method or predicate device.
- Qualifications of Experts: Not applicable for this specific type of device and study design.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable. The "ground truth" is established by the results of the comparative methods (predicate device and Hitachi 717 Assay for T Uptake), not through expert adjudication. Discrepancies would be handled through technical investigation of the assay performance, not by an adjudication panel.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study: No. A multi-reader multi-case (MRMC) comparative effectiveness study is not relevant for this type of in vitro diagnostic (IVD) reagent. MRMC studies are typically performed for imaging or interpretation-based diagnostic devices where human readers are involved in the diagnostic process.
6. Standalone (Algorithm Only) Performance
- Standalone Performance Study: Yes, in effect. The performance data presented (Assay Range, Precision, Correlation) directly reflects the standalone performance of the ACE® T Uptake Reagent as an algorithm/reagent system. There is no human-in-the-loop component in the fundamental operation of this quantitative assay. The device itself (ACE® T Uptake Reagent) is the "algorithm" and its performance is evaluated directly.
7. Type of Ground Truth Used
- Type of Ground Truth: The ground truth for the performance assessment was established through comparison with a legally marketed predicate device (Diagnostic Reagents, Inc. T Uptake Enzyme Immunoassay) and another commercial assay (Hitachi 717 Assay for T Uptake). Specifically, the correlation study used the results from these established methods as the reference for assessing the accuracy of the proposed device.
8. Sample Size for the Training Set
- Sample Size for Training Set: The document does not provide specific information about a dedicated "training set" sample size. For IVD reagents like this, the development process typically involves internal validation and optimization using various samples, but these are not usually formally termed "training sets" in the same way as machine learning algorithms. The performance assessment data N=50 likely represents a portion of the validation data.
9. How Ground Truth for the Training Set Was Established
- How Ground Truth for Training Set Was Established: As mentioned above, the concept of a "training set" and its explicit ground truth establishment is not typically documented in this manner for traditional IVD reagent submissions. The device's methodology (enzyme immunoassay) is based on established biochemical principles. Ground truth for optimizing and calibrating such a reagent would be derived from:
- Known concentration standards: Using commercially prepared or internally validated standards with defined T Uptake values.
- Reference materials: Using biological samples with assigned values from reference laboratories or methods.
- Comparison to existing, validated methods: Initial development and optimization would likely involve running samples in parallel with accepted methods to ensure the new reagent provides accurate and reliable results.
Overall, the study demonstrates substantial equivalence to the predicate device by showing comparable assay range, precision, and a strong correlation with both the predicate and another commercial T Uptake assay.
§ 862.1715 Triiodothyronine uptake test system.
(a)
Identification. A triiodothyronine uptake test system is a device intended to measure the total amount of binding sites available for binding thyroid hormone on the thyroxine-binding proteins, thyroid-binding globulin, thyroxine-binding prealbumin, and albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of thyroid disorders.(b)
Classification. Class II. 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.