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The Cholestech L·D·X Alanine aminotransferase Test (ALT) is for the in vitro quantitative determination of alanine aminotransferase (ALT) in whole blood or serum on the Cholestech L.D.X Analyzer.

Alanine aminotransferase measurements are used in the diagnosis and treatment of certain liver diseases (e.g., viral hepatitis and cirrhosis) and heart diseases.

The Cholestech L·D·X Alanine Aminotransferase Test (ALT) combines an enzymatic methodology and a solid-phase technology to measure ALT in whole blood or serum. Blood from a fingerstick is collected into a lithium heparin coated capillary tube (venous whole blood serum is also acceptable) and dispensed into a L·D·X cassette. The cassette is then placed into the Cholestech L·D·X where a unique system separates the plasma from the blood cells. The plasma flows to both sides of the cassette and is transferred to the ALT reaction pad.

The Cholestech L•D•X Analyzer measures alanine aminotransferase by an enzymatic method based on the method formulation of Katsuyama et al. Alanine aminotransferase catalyzes the transfer of amino groups from L-Alanine and α-Ketoglutarate to pyruvate and glutamate. Pyruvate oxidase, in the presence of oxygen, oxidizes the pyruvate to acetylphosphate and hydrogen peroxide. In a reaction catalyzed by horseradish peroxidase, the peroxide reacts with an indicator dye to form a blue color at a rate proportional to the ALT concentration of the sample. The resultant color in the reaction is measured by reflectance photometry.

L-Alanine + α -Ketoglutarate Alanine Aminotransferase → Pyruvate + Glutamate
Pyruvate + Phosphate + O2 + H2O Pyruvate Oxidase → Acetylphosphate + CO2 + H2O2
Indicator + H2O2 Peroxidase → Colored Blue Dye + H2O

A brown magnetic stripe on each cassette contains the calibration information required for the Cholestech L•D•X Analyzer to convert the reflectance reading to the ALT concentration in U/L at 37° C.

Here's an analysis of the provided text regarding the Cholestech L·D·X Alanine aminotransferase (ALT) Test, focusing on acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance

The submission primarily focuses on demonstrating substantial equivalence to a predicate device (Roche Diagnostics Reflotron GPT (ALT) test) rather than explicitly stating pre-defined acceptance criteria in the format of pass/fail thresholds. However, we can infer the performance characteristics the submitter aimed to demonstrate as being comparable or superior to the predicate.

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

• Precision Studies:
  • Within-run:
    • Cholestech L·D·X ALT: N=20 for each of 3 levels (Level 1, Level 2, Serum Pool).
    • Predicate: N=20 for each of 3 levels (Level I, Level II, Pool).
  • Total/Day to Day:
    • Cholestech L·D·X ALT: N=20 for each of 3 levels (Level 1, Level 2, Serum Pool).
    • Predicate: N=15 for each of 2 levels (Level I, Level II).
• Method Comparison Studies (Cholestech L·D·X ALT vs. predicate Reflotron GPT (ALT)):
  • Capillary Whole Blood (x) vs. Capillary Whole Blood (y): n = 24
  • Venous Whole Blood (x) vs. Venous Whole Blood (y): n = 53
  • Serum (x) vs. Serum (y): n = 52
• Method Comparison Studies (Predicate Reflotron GPT (ALT) vs. GPT (ALT) IFCC Method): (Note: This data is for the predicate device's performance against a reference method, not the current device.)
  • Venous Heparin Blood (x) vs. Heparin Plasma (y): n = 69
  • Serum (x) vs. Serum (y): n = 36
  • Venous Heparin Plasma (x) vs. Venous Heparin Plasma (y): n = 69
  • Capillary Heparin Blood (x) vs. Capillary Heparin Plasma (y): n = 26

Data Provenance: The document does not specify the country of origin for the data or whether the studies were retrospective or prospective. Given the nature of laboratory testing submissions, it is generally assumed these are prospective controlled studies conducted in a lab environment.

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

This type of information is not applicable to this submission. This device is an in vitro diagnostic (IVD) device for quantitative biochemical measurement (Alanine aminotransferase, ALT). The "ground truth" for such a device is typically established against a recognized reference method (like the IFCC method for ALT) or by comparison to a legally marketed predicate device with established clinical utility and accuracy. It does not involve human expert interpretation of images or clinical cases that would require adjudication.

4. Adjudication Method for the Test Set

This is not applicable. As explained above, the assessment of an IVD involves quantitative measurements and comparisons to reference methods or predicate devices, not human interpretation that requires adjudication.

5. Was a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Done? If so, what was the effect size of how much human readers improve with AI vs without AI assistance?

This is not applicable. This submission concerns an in vitro diagnostic assay (a lab test), not an AI-assisted diagnostic imaging device that would involve human readers interpreting cases. Therefore, no MRMC study or AI assistance effect size is mentioned or relevant.

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

This is not applicable. The Cholestech L·D·X ALT Test is a standalone IVD device (a test kit used with an analyzer), but it's not an AI algorithm. Its performance is inherent to the chemical reactions and reflectance photometry. The performance values reported (precision, method comparison) are the standalone performance of the device without human interpretation.

7. The Type of Ground Truth Used

The ground truth used for method comparison was primarily the predicate device, Roche Diagnostics Reflotron GPT (ALT) test, which itself was likely compared against a reference method such as the GPT (ALT) IFCC Method (as referenced in the predicate's method comparison section). For precision studies, the ground truth is the statistical properties of the measurements of known samples.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of machine learning or AI. For an IVD device like this, the "training" (calibration and optimization) of the assay methodology and the L·D·X Analyzer itself would have been done during the product development phase (R&D). The reported data represents performance characteristics verified subsequently. The sample sizes for these internal development and validation studies are not provided in this 510(k) summary.

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

As there is no explicit mention of a "training set" in the AI/ML sense, this question is not fully applicable. However, for the development and optimization of the assay and instrument (analogous to "training" for an IVD):

• The ground truth would have been established through known concentrations of ALT in control materials, reference methods (like the IFCC method), and potentially split-sample comparisons against established laboratory instruments.
• This process would involve extensive experimentation to optimize reagent concentrations, reaction times, measurement parameters, and calibration curves to ensure accuracy and precision across the intended assay range. The details of these internal R&D processes are typically proprietary and not provided in a 510(k) summary.

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