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ALFIS Vitamin D in conjunction with ALFIS-3 Analyzer is an enzyme-linked fluorescence immunoassay intended for in vitro diagnostic use at clinical laboratories for the quantitative measurement of Total 25-hydroxy Vitamin D (25-OH Vitamin D) in human serum, lithium heparin plasma and sodium heparin plasma.

ALFIS Vitamin D is indicated to be used as an aid in the determination of Vitamin D sufficiency in adults.

ALFIS-3 Analyzer is a fluorescence-scanning instrument using magnetic beads and alkaline phosphatase enzyme system for in vitro diagnostic use in conjunction with various ALFIS immunoassays intended for measuring the concentration of designated analytes in human blood and other specimens.

ALFIS Vitamin D Test Cartridge is a plastic structure molded in the form of a disposable, self-contained, unitized device which houses the 'magnetic bead', 'antibody-alkaline phosphatase-conjugator (Ab-ALP)', 'sample diluent', 'diethanolamine (DEA)', '4-Methylumbelliferyl phosphate (MUP)', 'washing buffer'; all of which are integral components of ALFIS Vitamin D test.

ALFIS Vitamin D test cartridge is an elongated structure having 150.8 mm length, 17 mm width and 16 mm height.

'ALFIS Vitamin D Test ID Chip' is a flat, rectangular device with its main body measuring 23 mm × 27 mm. Half of the portion along the breadth of the main body is 5 mm thick while remaining half is 3 mm in thickness. Another rectangular portion measuring 12 mm × 10 mm × 2 mm protrudes out from the breadth of apical side of the 3 mm-thick portion of the main body.

ALFIS Vitamin D Test ID Chip is an electronic memory device fitted into a plastic matrix. Lot-specific 'ALFIS Vitamin D Test ID Chip' is an integral component of ALFIS Vitamin D test system.

ALFIS-3 analyzer is a compact, bench-top, automated, fluorometric analyzer measuring 422 mm (L) x 270 mm (W) x 292 mm (H). ALFIS-3 weighs 13.0 kg.

ALFIS-3 analyzer is a fluorometer instrument of closed-system analyzer type.

'ALFIS Vitamin D Calibrators' needs to be tested by user laboratories for periodic calibration of ALFIS Vitamin D test system.

'ALFIS Vitamin D Controls' needs to be tested by user laboratories periodically for monitoring the performance of ALFIS Vitamin D test system.

The provided text describes the performance evaluation studies for the ALFIS Vitamin D and ALFIS-3 Analyzer system, which is an in vitro diagnostic device for quantitative measurement of Total 25-hydroxy Vitamin D.

Here's a breakdown of the requested information based on the provided document:

Acceptance Criteria and Device Performance

The document doesn't explicitly state "acceptance criteria" in a tabular format with specific numerical targets for each parameter (e.g., "LoD < X ng/mL"). Instead, it describes how each performance characteristic was evaluated and the resulting performance data, often concluding that the results are "acceptable" or "insignificant interference." However, we can infer the acceptance for some parameters from the reported findings. For instance, for linearity, the high R² value (0.9998) demonstrates acceptable linearity. For precision (repeatability and reproducibility), the CV < 10% is explicitly stated as indicating acceptability. For LoQ, the target of CV ≤ 20% is mentioned.

Here's a table summarizing the reported device performance, with inferred acceptance criteria where explicit values are not provided as a target but rather indirectly through the statement of acceptability:

Study Details

Here's the detailed information regarding the studies:

1. A table of acceptance criteria and the reported device performance: (Refer to the table above).

2. Sample sizes used for the test set and the data provenance:

   • Limit of Blank (LoB): 72 blank replicates per lot/analyzer pair (total 3 lots, 3 analyzers) tested across 3 days. This implies 72 * 3 = 216 replicates in total.
   • Limit of Detection (LoD): 15 replicates per lot/analyzer pair (total 3 lots, 3 analyzers) for each of 4 low 25-hydroxyvitamin D-spiked serum samples. Total 45 * 4 = 180 replicates for samples (plus an unstated number for blanks).
   • Limit of Quantitation (LoQ): 12 replicates per lot/analyzer pair (total 3 lots, 3 analyzers) for each of 5 low 25-hydroxyvitamin D serum samples. Total 36 * 5 = 180 replicates for samples.
   • Linearity: 19 25-hydroxyvitamin D-spiked serum samples, tested in triplicate. Total 19 * 3 = 57 measurements.
   • High-dose Hook Effect: A series of spiked samples (10 concentrations from 12.5 ng/mL to 1000 ng/mL), tested in triplicate. Total 10 * 3 = 30 measurements.
   • Analytical Specificity (Interference): The specific number of samples for each interferent is not explicitly stated (e.g., "Performance... not been found to be significantly affected when the endogenous and exogenous substances were tested at specified highest concentrations").
   • Analytical Specificity (Cross-reactivity): The specific number of samples for each cross-reactant is not explicitly stated.
   • In-house repeatability and reproducibility:
     • Repeatability: 3 spiked serum samples, tested in duplicate daily for 20 successive days. Total 3 * 2 * 20 = 120 measurements.
     • Reproducibility: 3 spiked serum samples, tested in quintuplicate daily for 5 successive days (with 3 cartridge lots/analyzer/operator pairs). Total 3 * 5 * 5 = 75 measurements per lot/analyzer/operator pair for reproducibility (75 * 3 = 225 total).
   • External site-to-site reproducibility: 3 spiked serum samples, tested in quintuplicate daily for 5 successive days (across 3 sites/cartridge lots/analyzer-operators). Total 3 * 5 * 5 = 75 measurements per site, so 75 * 3 = 225 in total.
   • Matrix Comparison: 45 matching clinical serum, lithium heparin plasma, and sodium heparin plasma samples, plus an additional 5 spiked samples. Total 45 + 5 = 50 samples per matrix type.
   • Reference Interval: Serum samples collected from 299 apparently healthy adults in the United States. Data provenance is specified as US (central, northern, southern states), collected from external clinical sample repositories.
   • Method Comparison Study: 120 CDC VDSCP verification samples. Provenance of these samples is implied as US (CDC samples). The study was carried out at the "in-house laboratory."

   Data Provenance (Retrospective/Prospective): The document does not explicitly state whether the samples were collected retrospectively or prospectively for most studies. However, for the "Reference Interval" study, it mentions "samples collected from 299 apparently healthy adults in the United States," and "sample sets procured... met the following criteria: ...Collected after June 2021", which suggests recent, potentially prospective, collection or procurement for the study. For the method comparison, CDC VDSCP verification samples are typically existing, well-characterized samples, suggesting a retrospective use of these samples for the study.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: This information is not provided. For this type of IVD device (quantitative measurement of a biomarker), "ground truth" is typically established by certified reference methods, not human expert interpretation in the way it would be for an imaging AI device.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable for this type of quantitative IVD device. Ground truth is established by analytical methods or reference measurement procedures (RMP).

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 device is an automated immunoassay system, not an AI-assisted diagnostic tool requiring human reader studies or MRMC.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: The device itself is an automated, standalone system (ALFIS-3 Analyzer in conjunction with ALFIS Vitamin D cartridges) designed to measure 25-OH Vitamin D quantitatively without direct human interpretation of a visual output. The device results are numerical values. The performance studies (LoB, LoD, LoQ, Linearity, Precision, Analytical Specificity, Matrix Comparison, Method Comparison) all represent the "standalone" performance of the system.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

   • For LoB, LoD, LoQ, Linearity, High-dose Hook, Analytical Specificity, Repeatability, Reproducibility, Matrix Comparison: Ground truth is based on the known concentrations of spiked samples or reference materials, or properties of the substances themselves.
   • For Method Comparison: Ground truth for the samples was established by the Reference Measurement Procedure (RMP) of 25-hydroxyvitamin D, i.e., ID-LC-MS/MS at a CDC certified laboratory with NIST standard reference material 2972. This is a highly robust and accepted method for establishing ground truth in clinical chemistry.

8. The sample size for the training set: Not applicable for this type of immunoassay device. The device operates based on a pre-defined enzyme-linked fluorescence immunoassay protocol, not a machine learning algorithm that requires a "training set" in the computational sense. The "training" for the device would involve calibration using provided calibrators.

9. How the ground truth for the training set was established: Not applicable. The "training set" concept doesn't apply here. However, for calibration, the instructions state that "ALFIS Vitamin D Calibrators" are used, with approximate assigned 25-OH Vitamin D levels (10 ng/mL and 40 ng/mL), and that a "Lot-specific master calibration curve/equation is encoded in the 'Lot-specific ALFIS Vitamin D Test ID Chip'." This implies that the calibrators' "ground truth" levels (or reference values) are pre-established by the manufacturer, likely traceable to a recognized standard such as the CDC RMP.

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