(83 days)
The FT4L method is an in vitro diagnostic test for the quantitative measurement of Free Thyroxine in human serum and plasma on the Dimension® EXL™ with LM system. Measurements of free thyroxine are used in the diagnosis and monitoring of thyroid disease.
The LOCI® Thyroid Calibrator is an in vitro diagnostic product for the calibration of the FT4L method on the Dimension® EXLTM with LM system.
The Dimension® EXL™ with LM system is an in vitro diagnostic device that is intended to measure a variety of analytes in human body fluids. The system utilizes photometric, turbidimetric, chemiluminescence and integrated ion selective multisensor technology for chemical and immunochemical applications for clinical use.
The Dimension® EXL™ with LM clinical chemistry system is a floor model, fully automated, microprocessor-controlled, integrated instrument system which uses prepackaged Dade Behring Flex® reagent cartridges to measure a variety of analytes in human body fluids. The system can process samples in random access, batch or stat modes.
The Dimension® FT4L Flex® reagent cartridge is an in vitro diagnostic device that consists of prepackaged reagents in a plastic eight-well cartridge for use on the Dimension® EXL™ with LM system.
The LOCI® Thyroid Calibrator is a liquid, bovine serum albumin based product containing thyroxine. There are four calibrator levels with target values of 0.8, 1.6, 4.0 and 8.4 ng/dL.
The provided text describes a 510(k) premarket notification for the Dimension® EXL™ with LM clinical chemistry system, Dimension® FT4L Flex® reagent cartridge, and LOCI® Thyroid Calibrator. The primary study described is a method comparison study between the new Dimension® FT4L Flex® reagent cartridge and its predicate device, the Dimension® Vista FT4 Flex® reagent cartridge.
Here's an analysis of the acceptance criteria and study details based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined quantitative acceptance criteria (e.g., "slope must be between 0.95 and 1.05 and r > 0.98"). However, the study aims to demonstrate "excellent correlation" and substantial equivalence to the predicate device. The results indicate that this goal was met.
| Metric | Acceptance Criteria (Implied by "excellent correlation" and "substantial equivalence") | Reported Device Performance (Dimension® FT4L Flex® vs. Dimension® Vista FT4 Flex®) |
|---|---|---|
| Correlation Coefficient (r) | High correlation (e.g., > 0.98 for strong agreement) | 0.999 (Demonstrates excellent correlation) |
| Slope | Close to 1 (indicating proportional agreement) | 0.97 |
| 95% CI for Slope | Narrow interval around 1 | 0.96-0.97 |
| Y-intercept | Close to 0 (indicating no constant bias) | -0.03 |
| Sy,x (Standard Error of the Estimate) | Low value (indicating small scatter around the regression line) | 0.08 ng/mL |
2. Sample Size and Data Provenance
- Sample Size for Test Set: One hundred-and-eighty (180) serum samples.
- Data Provenance: Not explicitly stated whether the data is retrospective or prospective, nor the country of origin. It's common for such studies to use prospectively collected samples or a mix, but this information is absent.
3. Number of Experts and Qualifications for Ground Truth
The study described is a method comparison study between two in vitro diagnostic devices. It does not involve human interpretation or subjective assessment that would require experts to establish a "ground truth" in the traditional sense (like in image analysis or clinical diagnosis). Instead, the "ground truth" in this context is the measurement obtained from the predicate device.
4. Adjudication Method
Not applicable. This was a direct comparison of measurements between two automated analytical methods, not a study requiring adjudication of subjective interpretations.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, an MRMC comparative effectiveness study was not done. This study focuses on the analytical performance of an in vitro diagnostic assay, comparing its measurements to a predicate device. It does not assess the diagnostic effectiveness with or without AI assistance for human readers.
6. Standalone (Algorithm Only) Performance
Yes, the study primarily assesses the standalone performance of the Dimension® FT4L Flex® reagent cartridge on the Dimension® EXL™ with LM system by comparing its quantitative measurements to those of the predicate device. The "algorithm" here refers to the entire analytical process of the device, from reagent interaction to signal detection and calculation.
7. Type of Ground Truth Used
The ground truth used for the comparison was the measurements obtained from the predicate device, the Dimension® Vista FT4 Flex® reagent cartridge. This is a common approach for demonstrating substantial equivalence for new in vitro diagnostic devices.
8. Sample Size for Training Set
The document does not explicitly mention a "training set" or "training data" in the AI/machine learning sense. For in vitro diagnostic devices, method comparison studies typically use a test set to validate performance against a predicate. If method development and internal validation occurred, they would have used various samples, but these are not referred to as a "training set" in this context and their size is not provided.
9. How Ground Truth for Training Set Was Established
Not applicable, as a "training set" in the machine learning sense is not described. For the general development of such IVD assays, ground truth for initial development and calibration would typically be established using reference materials, certified calibrators, and samples characterized by a reference method or highly accurate established methods. However, these details are not provided in the summary.
§ 862.1695 Free thyroxine test system.
(a)
Identification. A free thyroxine test system is a device intended to measure free (not protein bound) thyroxine (thyroid hormone) in serum or plasma. Levels of free thyroxine in plasma are thought to reflect the amount of thyroxine hormone available to the cells and may therefore determine the clinical metabolic status of thyroxine. Measurements obtained by this device are used in the diagnosis and treatment of thyroid diseases.(b)
Classification. Class II.