(28 days)
The TSH method is used on the Dimension® RxL clinical chemistry system with the heterogeneous immunoassay module to quantitatively measure TSH in human serum and plasma. Measurements of TSH aid in the diagnosis of thyroid or pituitary disorders.
The TSH method is a one-step enzyme immunoassay. Sample is incubated with chromium dioxide particles (CrO2) coated with monoclonal antibodies specific for the intact TSH molecule and conjugate reagent [alkaline phosphatase (ALP) labeled monoclonal antibodies specific for the TSH beta subunit] to form a particle/TSH/conjugate sandwich. Unbound conjugate and analyte are removed by magnetic separation and washing. The sandwich bound ALP initiates an amplification cascade. ALP dephosphorylates synthetic flavin adenine dinucleotide phosphate (FADP) to give FAD. FAD binds to APO d-amino acid oxidase and converts it to active holo d-amino acid oxidase. Each molecule of holo d-amino acid oxidase then produces multiple molecules of hydrogen peroxide (H2O2), which in the presence of horseradish peroxidase (HRP), converts 3,5-dichloro-2-hydroxybenzenesulfonic acid (DCHBS) and 4-aminoantipyrine (4-AAP) to a colored product that absorbs at 510nm. The color measured is directly proportional to the concentration of TSH present in the patient sample.
Here's an analysis of the provided text regarding the acceptance criteria and supporting study, formatted as requested:
Acceptance Criteria and Device Performance
This document describes a diagnostic device, the Dade International TSH Method, and its comparison to a predicate device, the Abbott AxSYM® Ultrasensitive hTSH. The primary way the device demonstrates equivalence and thus performance is through a direct comparison study against this predicate.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied by Predicate Comparison) | Reported Device Performance (Dade International TSH Method vs. Abbott AxSYM® Ultrasensitive hTSH) |
|---|---|
| High Correlation (R-value) | 0.99 |
| Slope close to 1.0 | 1.06 |
| Intercept close to 0.0 µIU/mL | -0.03 µIU/mL |
| Qualitative Equivalence (Principle and Performance) | Stated as "substantially equivalent in principle and performance" based on the comparison study. |
Study Proving Device Meets Acceptance Criteria
The study described is a split sample comparison between the Dade International TSH method on the Dimension® RxL clinical chemistry system and the Abbott AxSYM® Ultrasensitive hTSH assay.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: 86 clinical patient samples.
- Data Provenance: The document refers to "clinical patient samples." It does not specify the country of origin. The study appears to be retrospective in nature, as it uses existing patient samples for comparison.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
- Not Applicable. This type of diagnostic device (immunoassay) is not typically evaluated by human experts establishing "ground truth" in the same way an image analysis AI might be. Instead, the "ground truth" for comparison is established by the performance of the predicate device, which is an already FDA-cleared and accepted diagnostic tool. The performance of the predicate device is considered the reference standard in this context.
4. Adjudication Method for the Test Set
- Not Applicable. As the comparison is between two automated diagnostic assays, there is no human adjudication process involved in resolving discrepancies between results. The raw measurements from both devices are compared statistically.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No. This is not an MRMC study. MRMC studies are typically used for evaluating the effectiveness of AI in assisting human readers in interpreting medical images. This study evaluates an automated diagnostic assay's performance against a predicate device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes. This study evaluates the standalone performance of the Dade International TSH Method (the "algorithm only") by comparing its output directly to the output of the predicate device. There is no human intervention in the result generation or interpretation for either device within this comparison.
7. The Type of Ground Truth Used
- Predicate Device Performance: The "ground truth" in this context is established by the results obtained from the Abbott AxSYM® Ultrasensitive hTSH assay, which serves as the reference standard. This is a common approach for demonstrating substantial equivalence for new diagnostic devices.
8. The Sample Size for the Training Set
- Not specified/Not applicable for this type of submission. This document describes a traditional immunoassay, not a machine learning or AI algorithm that would typically involve a "training set" for model development. The development process for an immunoassay involves reagent optimization, calibration, and validation, rather than machine learning training.
9. How the Ground Truth for the Training Set was Established
- Not applicable. As stated above, there is no "training set" in the context of an AI/ML algorithm for this specific device and submission type. The "ground truth" for the predicate comparison is the predicate device's output.
§ 862.1690 Thyroid stimulating hormone test system.
(a)
Identification. A thyroid stimulating hormone test system is a device intended to measure thyroid stimulating hormone, also known as thyrotrophin and thyrotrophic hormone, in serum and plasma. Measurements of thyroid stimulating hormone produced by the anterior pituitary are used in the diagnosis of thyroid or pituitary disorders.(b)
Classification. Class II.