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The LIAISON® 25 OH Vitamin D Assay uses chemiluminescent immunoassay (CLIA) technology intended for the quantitative determination of 25hydroxyvitamin D (25-OH-D) and other hydroxylated vitamin D metabolites in human serum or plasma to be used in the assessment of vitamin D sufficiency. Assay results should be used in conjunction with other clinical and laboratory data to assist the clinician in making individual patient management decisions in an adult population

The method for quantitative determination of 25 OH Vitamin D is a direct, competitive chemiluminescence immunoassay (CLIA). Specific antibody to Vitamin D is used for coating magnetic particles (solid phase) and Vitamin D is linked to an isoluminol derivative. During the incubation, 25 OH Vitamin D is dissociated from its binding protein, and competes with labeled Vitamin D for binding sites on the antibody. After the incubation, the unbound material is removed with a wash cycle, Subsequently, the starter reagents are added and a flash chemiluminescent reaction is initiated. The light signal is measured by a photomultiplier as relative light units (RLU) and is inversely proportional to the concentration of 25 OH Vitamin D present in calibrators, controls, or samples.

The provided text describes the LIAISON® 25 OH Vitamin D Assay, a chemiluminescent immunoassay for the quantitative determination of 25-hydroxyvitamin D (25-OH-D) and other hydroxylated vitamin D metabolites in human serum or plasma.

Here's an analysis of the acceptance criteria and study information:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and the data provenance

The document does not explicitly define a "test set" in the context of a machine learning study. Instead, it describes performance characteristics of an in-vitro diagnostic device:

• Analytical sensitivity: Tested with "three lots of materials."
• Functional sensitivity: Determined from "serial dilutions." (Number of samples not specified).
• Total precision: Not explicitly stated, but "across the range of the assay according to NCCLS guidelines" implies multiple samples and runs.
• Linearity: Not specified, but "$y = 0.98x + 4.1; r = 0.98$" suggests a range of concentrations were tested.
• Endogenous Substance Interference: Likely tested with spiked samples, but the number is not specified.
• Sample Types: "Serum and EDTA plasma matrices" were compared.
• Sample Stability: Involved storing samples at different temperatures and subjecting them to freeze/thaw cycles.
• Carry-over: Tested low concentration samples directly after high concentration samples.
• Correlation with Predicate Device: Not explicitly stated, but "correlated well with the DiaSorin RIA method" implies a comparative study with an unspecified number of samples.
• Reference Range: Established using 98 samples from "apparently healthy normal volunteers."
• Data Provenance: The 98 samples for reference range were "collected in the southwestern United States in late autumn." All data relate to the performance of the assay itself and are considered prospective for the device evaluation.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

Not applicable. This is an in vitro diagnostic device for quantitative determination of a biomarker, not an imaging device or AI for diagnosis that requires expert readers for ground truth. The "ground truth" for the performance characteristics typically refers to established analytical methods, reference materials, or clinical outcomes, rather than expert interpretation of images/data.

4. Adjudication method for the test set

Not applicable, as it's not a reader-based study requiring adjudication. The performance is assessed against analytical standards and comparative methods.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

Not applicable. This is an in vitro diagnostic assay, not an AI-assisted diagnostic tool involving human readers interpreting cases.

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

Yes, the study describes the standalone performance of the LIAISON® 25 OH Vitamin D Assay. The results presented (sensitivity, precision, linearity, etc.) are inherent to the device and its analytical process, without human interpretation as part of the primary measurement. The assay outputs a quantitative value directly.

7. The type of ground truth used

The "ground truth" for evaluating this assay's performance would be:

• Reference Methods/Standards: For analytical sensitivity, linearity, and recovery, results are compared against known concentrations or established reference methods.
• Clinical Samples: For precision, interference, sample type equivalence, and stability, the assay's performance on clinical samples is assessed.
• Predicate Device: For method correlation, the LIAISON® assay's results are compared against the DiaSorin 25-Hydroxyvitamin D 125I RIA predicate device.
• Statistically Derived Normal Ranges: The reference range was established by measuring 98 samples from healthy individuals and calculating percentiles (2.5th to 97.5th).

8. The sample size for the training set

Not applicable in the typical sense for machine learning. This is a traditional immunoassay, not a machine learning algorithm that requires a "training set." The assay is developed based on chemical and biological principles. If you consider "development" as analogous to training, the inputs would be reagents, antibodies, and known standards used during the assay development and optimization phases.

9. How the ground truth for the training set was established

Not applicable for a traditional immunoassay. For the development of the assay, the "ground truth" for calibrators and controls would be established using highly characterized standards (e.g., gravimetric preparation, reference methods) with known concentrations of 25-OH Vitamin D.

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