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VIDAS® CA 125 II is an automated quantitative test for use on the VIDAS instruments, for the measurement of OC 125 reactive antigenic determinants in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS CA 125 II is indicated for the serial measurement of OC 125 reactive antigenic determinants as an aid in the monitoring of patients previously diagnosed with Stage IV (metastatic) ovarian cancer for disease progression or response to therapy. The VIDAS CA 125 II assay can also be used as an aid in the early detection of recurrence in previously treated Stage II and III ovarian cancer patients.

VIDAS® CA 125 II is an automated quantitative test for use on the VIDAS instruments, for the measurement of CA 125 reactive antigenic determinants in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS CA 125 II is indicated for the serial measurement of OC 125 reactive antigenic determinants as an aid in the monitoring of patients previously diagnosed with Stage IV (metastatic) ovarian cancer for disease progression or response to therapy. The VIDAS CA 125 II assay can also be used as an aid in the early detection of recurrence in previously treated Stage II and III ovarian cancer patients.

CA 125 II is a registered trademark from Fujirebio Diagnostics Inc. (formerly named Centocor Diagnostics of Pennsylvania, Inc.)

The assay principle combines a two-step immunoassay sandwich method with a final fluorescent detection (ELFA). The Solid Phase Receptacle (SPR), a pipette tip-like device, serves as the solid phase as well as the pipetting device for the assay. It is coated with mouse monoclonal M 11 antibodies. The other assay reagents are ready-to-use and pre-dispensed in the sealed reagent strips (STRs). The individual kit components are described in detail on the following pages.

All of the assay steps are performed automatically by the instrument. The reaction medium is cycled in and out of the SPR several times. This operation enables the monoclonal M11 antibody fixed onto the interior wall of the SPR to capture the reactive antigenic determinants present in the sample. Unbound components are eliminated during the washing steps. Alkaline phosphatase labeled mouse monoclonal OC 125 antibody (conjugate) is then incubated in the SPR where it binds with the OC 125 reactive antigenic determinant. Unbound conjugate is then eliminated during the washing steps.

During the final detection step, the substrate (4-Methyl-umbelliferyl phosphate) is cycled in and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product (4-Methyl-umbelliferone) the fluorescence of which is measured at 450 nm. The intensity of the fluorescence is proportional to the concentration of OC 125 reactive antigenic determinants present in the sample.

At the end of the assay, results are automatically calculated by the instrument in relation to the calibration curve stored in memory, and then printed out.

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

Acceptance Criteria and Device Performance for VIDAS® CA 125 II Assay

1. Table of Acceptance Criteria and Reported Device Performance

The document describes performance characteristics rather than explicit "acceptance criteria" with pass/fail thresholds. However, we can infer the tested performance against predicate device or established analytical goals.

• Between-site CV: 4.15%
• Between-lot CV: 1.01%
• Between-recalibration CV: 1.87%
• Between-day CV: 0.00%
• Between-run CV: 0.99%
• Within-run CV: 3.40%
• Total CV: 5.85%

Pool B (75.3 U/mL):

• Between-site CV: 2.13%
• Between-lot CV: 0.00%
• Between-recalibration CV: 2.26%
• Between-day CV: 1.08%
• Between-run CV: 2.00%
• Within-run CV: 3.50%
• Total CV: 5.20%

Pool C (18.9 U/mL):

• Between-site CV: 2.43%
• Between-lot CV: 0.79%
• Between-recalibration CV: 1.96%
• Between-day CV: 0.74%
• Between-run CV: 1.79%
• Within-run CV: 3.35%
• Total CV: 5.03% |
  | Measurement Range | Clearly defined and clinically relevant. | 4.00 - 600.00 U/mL |
  | Analytical Detection Limit (LoB/LoQ) | Below the lower limit of the measurement range. | Estimated to be less than 4 U/mL. |
  | Hook Effect | No significant hook effect at high concentrations. | No hook effect found up to 200,000 U/mL. |
  | Method Comparison (vs. Predicate) | Strong correlation and agreement with a legally marketed predicate device (TOSOH ST AIA Pack CA 125). Implicitly, the Deming regression parameters (slope, intercept, and their confidence intervals) and overall correlation should demonstrate substantial equivalence. | Comparison Study:
• N = 210 samples (including 77 ovarian cancer patients and 133 monitoring samples)
• Equation: Y = 0.93X - 58.10
• 95% Confidence Interval for Intercept: -169.15 to 52.95
• 95% Confidence Interval for Slope: 0.61 to 1.25
• Range of samples: VIDAS: 4.0 - 31801 U/mL; Predicate: 2.0 - 29940 U/mL
• Conclusion: The device is considered substantially equivalent to the predicate. |

2. Sample Size and Data Provenance for Test Set (Method Comparison)

• Sample Size: 210 samples. This includes 77 samples from women with ovarian cancer and 133 samples for monitoring disease status.
• Data Provenance: The document does not explicitly state the country of origin. It indicates the samples were serum samples from women with ovarian cancer. It implies a retrospective or a mixed prospective/retrospective design, as samples were "randomly chosen" from existing patient populations.

3. Number of Experts and Qualifications for Ground Truth (Test Set)

Not applicable. This device is an in vitro diagnostic (IVD) for quantitative measurement of a biomarker. The "ground truth" for the method comparison study is the result obtained from the predicate device (TOSOH ST AIA Pack CA 125). There are no human experts involved in establishing a subjective ground truth for the CA 125 values.

4. Adjudication Method for Test Set

Not applicable. As described above, this is a quantitative measurement comparison, not a study requiring human expert adjudication of a subjective finding. The comparison is against the predicate device's quantitative results.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This type of study is typically performed for imaging or other diagnostic tools where human readers interpret results, and the AI's effect on their performance is evaluated. The VIDAS® CA 125 II Assay is a fully automated quantitative immunoassay.

6. Standalone (Algorithm Only) Performance Study

Yes, the studies described (Precision, Measurement Range, Analytical Detection Limit, Hook Effect, and Comparison with other methods like the predicate device) represent the standalone performance of the VIDAS® CA 125 II Assay. It is an automated system without a human-in-the-loop for the quantification process itself.

7. Type of Ground Truth Used

• For Precision, Measurement Range, Analytical Detection Limit, Hook Effect: These are analytical performance characteristics where the "ground truth" is established through well-defined laboratory analytical methods and controls, ensuring intrinsic performance of the assay.
• For Method Comparison: The "ground truth" for comparison was the quantitative results obtained from the predicate device (TOSOH ST AIA Pack CA 125 Enzyme Immunoassay). The goal was to demonstrate substantial equivalence to an already legally marketed device.

8. Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of machine learning, as this is an immunoassay, not an AI/ML-based diagnostic algorithm. However, calibration curves are established for each kit lot and calibrator lot. The number of samples used to establish these master curves is not specified, but it's an internal process traced to working standards.

9. How the Ground Truth for the Training Set (Calibration) was Established

For the VIDAS® CA 125 II Assay, the equivalent of "ground truth" for its internal calibration (referred to as master curves and calibrator lots) is established by:

• Traceability to working standards established by bioMérieux, Inc.
• Value assignment by the Fujirebio Diagnostics, Inc. radioimmunoassay method.

This indicates a hierarchical system where internal standards are calibrated against a recognized reference method to ensure accuracy and consistency.

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