(204 days)
The VIDAS® D-Dimer New assay is intended for use as an aid in the diagnosis of deep venous thrombosis and pulmonary embolism disease.
The VIDAS® D-Dimer New (DD2) Assay is an automated quantitative test for use on the VIDAS instrument (K891385) for the immunoenzymatic determination of fibrin degradation products (FbDP) in human plasma using the enzyme-linked fluorescent immunoassay (ELFA) technique. The instrument controls all assay steps and assay temperatures. A pipette tip-like disposable device, the Solid Phase Receptacle (SPR), serves as the solid phase as well as a pipettor for the assay. Reagents for the assay are ready-to-use and pre-dispensed in the sealed DD2 Reagent Strips.
The assay principle combines a two-step enzyme immunoassay sandwich method with a final fluorescent detection (ELFA). The Solid Phase Receptacle (SPR) serves as the solid phase with the anti-FbDP monoclonal (mouse) antibodies P10B5E12C9 adsorbed on its surface, as well as the pipetting device for the assay.
The instrument performs all of the assay steps automatically. The reaction medium is cycled in and out of the SPR several times according to a specified protocol.
The sample is taken and transferred into the well containing the conjugate, which is an alkaline phosphatase-labeled anti-FbDP monoclonal (mouse) antibodies (P2C5A10) The sample/conjugate mixture is cycled in and out of the SPR several times to increase the reaction speed. The antigen binds to antibodies coated on the SPR and to the conjugate forming a "sandwich".
In the second step, the remaining free antigen sites are saturated by cycling the conjugate in the fifth well of the strip in and out of the SPR. Unbound components are eliminated during the washing steps.
Two detection steps are then performed successively. During each 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-Methylumbelliferone), the fluorescence of which is measured at 450 nm. The intensity of the fluorescence is proportional to the concentration of antigen present in the sample.
At the end of the assay, results are automatically calculated by VIDAS in relation to two calibration curves stored in memory corresponding to the two detection steps. A threshold signal determines the choice of the calibration curve to be used for each sample. The results are then printed out.
The acceptance criteria and study proving the device meets them are outlined below:
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state quantitative acceptance criteria for each metric (Sensitivity, Specificity, Negative Predictive Value) prior to presenting results. Instead, it demonstrates the performance of the new DD2 Assay in comparison to the predicate DD Assay. The implicit acceptance criteria appear to be substantial equivalence or improvement over the predicate device.
| Performance Metric | DD2 Assay Performance (All VTE Suspects) | DD Assay Performance (Predicate, All VTE Suspects) |
|---|---|---|
| Sensitivity | 100% (95% CI, 95.0-100) | 98.6% (95% CI, 92.5-100) |
| Specificity | 33.0% (95% CI, 27.0-39.1) | 40.4% (95% CI, 34.1-46.8) |
| Negative Predictive Value | 100% (95% CI, 95.3-100) | 98.9% (95% CI, 94.2-100) |
| Correlation (0-10000 ng/mL) | Slope: 0.9994, Ordinate: 42.972, R: 0.9832 | N/A (Comparison with DD2) |
| Correlation ( |
§ 864.7320 Fibrinogen/fibrin degradation products assay.
(a)
Identification. A fibrinogen/fibrin degradation products assay is a device used to detect and measure fibrinogen degradation products and fibrin degradation products (protein fragments produced by the enzymatic action of plasmin on fibrinogen and fibrin) as an aid in detecting the presence and degree of intravascular coagulation and fibrinolysis (the dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels).(b)
Classification. Class II (performance standards).