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The Dimension® TACR Flex® reagent cartridge is an in vitro diagnostic test intended to quantitatively measure tacrolimus in human whole blood on the Dimension® clinical chemistry system. Measurements of tacrolimus are used as an aid in the management of tacrolimus therapy in kidney and liver transplant patients.

The Dimension® TACR Flex® reagent cartridge is an in vitro diagnostic device that consists of prepackaged reagents in a plastic eight-well cartridge for use on the Dade Behring Dimension® clinical chemistry system.

The provided text describes a 510(k) premarket notification for the Dimension® TACR Flex® reagent cartridge, an in vitro diagnostic device used to measure tacrolimus in human whole blood. The submission aims to demonstrate substantial equivalence to a predicate device, the Abbott IMx® Tacrolimus II Assay.

Here's an analysis of the acceptance criteria and study information based on your request:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state acceptance criteria in terms of pre-defined thresholds for slope, intercept, or correlation coefficient. Instead, it presents the results of method comparison studies and implies that these results are considered acceptable for demonstrating substantial equivalence. The predicate device's assay range (1.5-30 ng/mL) is a point of comparison for the new device's range (1.2-30 ng/mL).

However, based on the provided comparative method tables, we can deduce what was measured:

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

• Sample Size for Test Set:
  • Vs. LC/MS/MS: 184 samples (103 kidney, 81 liver)
  • Vs. Abbott IMx® Tacrolimus II Assay: 175 samples (97 kidney, 78 liver)
• Data Provenance:
  • Country of Origin: Not explicitly stated, but the studies were conducted at "two external sites." This usually implies clinical sites within the country where regulatory approval is sought (e.g., USA for FDA submission) unless specified otherwise.
  • Retrospective or Prospective: Not explicitly stated. However, "samples from 2 transplant patient groups (liver and kidney) were included in the studies" suggests these were patient samples collected for the purpose of the study, making it likely a prospective or retrospectively collected cohort specifically for this validation. Given the date of submission (2006), it's more probable that these were prospectively collected samples from transplant patients.

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

This information is not applicable to this type of device. For in vitro diagnostic assays measuring a quantitative analyte like tacrolimus, the "ground truth" is typically established by a highly sensitive and specific reference method (like LC/MS/MS) or a well-established, legally marketed comparative method (like the Abbott IMx® assay). There are no human experts involved in "scoring" or "interpreting" the results to establish ground truth in the way there would be for image-based diagnostic AI.

4. Adjudication Method for the Test Set

This is not applicable. Adjudication methods (like 2+1, 3+1) are used to resolve discrepancies in human expert interpretations, especially in studies involving subjective assessments (e.g., image-based diagnostics). For quantitative chemical assays, the agreement is determined mathematically by statistical methods (e.g., Passing Bablok regression) between the test device and the reference/predicate method.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size of Human Improvement with AI vs. Without AI Assistance

This information is not applicable. This device is an in vitro diagnostic reagent cartridge for laboratory testing, not an AI-assisted diagnostic tool that aids human readers (e.g., radiologists interpreting images). Therefore, no MRMC study or AI assistance effect size is relevant.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the studies presented are essentially standalone performance studies of the Dimension® TACR Flex® reagent cartridge. The device provides a quantitative measurement of tacrolimus. Its performance is evaluated directly against established methods (LC/MS/MS and the Abbott IMx® Tacrolimus II Assay) without human intervention in the result generation itself. The results (slope, intercept, r-value) characterize the algorithm/device's performance.

7. The Type of Ground Truth Used

The ground truth used was:

• Reference Method: Liquid Chromatography / Tandem Mass Spectrometry (LC/MS/MS)
• Comparative Method: Abbott IMx® Tacrolimus II Assay (a predicate device)

8. The Sample Size for the Training Set

The document does not explicitly mention a separate training set for this device. For in vitro diagnostic assays like this, it is common that:

• The assay's formulation and optimization would occur during development using a variety of samples and calibrators, which could be considered an internal "training" phase for the assay itself.
• The statistical analysis (Passing Bablok regression) is performed on the entire test set against the reference or predicate method.

If the device involved a machine learning algorithm, a dedicated training set would be described. Since it's an immunoassay, the "training" analogous to ML would be the assay development and calibration process. The document only describes the validation (test set) data.

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

As no specific "training set" for an explicit algorithm is mentioned, this question is not directly applicable. For the development and calibration of the immunoassay, the "ground truth" would be established using:

• Highly purified tacrolimus standards.
• Reference methods like LC/MS/MS to assign values to calibrator materials.
• Internal validation and quality control procedures.

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