(42 days)
The REAADS Protein S Antigen Test Kit is an in vitro diagnostic assay for the quantitative determination of Total and Free Protein S levels in human plasma (as a percentration) by enzyme-linked immunosorbent assay (ELISA). Plasma levels of Protein S may be used in conjunction with the results from other assays as an aid in diagnosing congenital or acquired Protein S deficiencies associated with thrombotic disease.
The REAADS Protein S Antigen Test Kit is a sandwich enzyme linked immunosorbent assay (ELISA). A capture antibody specific for human Protein S is coated to 96-microwell polystyrene plate. Diluted patient plasma is incubated in the wells, allowing any available Protein S to bind to the anti-human Protein S antibody on the microwell surface. The plates are washed to remove any unbound plasma molecules. Bound Protein S is quantitated using an HRP conjugated anti-human Protein S detection antibody. Any unbound conjugated antihuman Protein S is washed away after an incubation period. A chromogenic substrate of tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) is added to develop a colored reaction. The intensity of the color is measured spectrophotometrically at 450nm in optical density (O.D.) units. Protein S relative percent concentrations in patient plasma are determined against a curve prepared from a reference plasma provided with the kit. Results obtained from diluted plasma samples not pretreated with polyethylene glycol (PEG) represent the Total Protein S concentration from that sample. To measure Free Protein S, PEG is added to plasma samples prior to beginning the assay to precipitate the Protein S-C4b binding protein complex. The supernatant fraction containing Free Protein S may be tested along with the untreated plasma sample. Both Total (untreated) and Free (PEG-treated) Protein S concentrations are determined following the same assay procedure described using separate reference curves.
- Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Device Performance (Total Protein S) | Device Performance (Free Protein S) |
|---|---|---|
| Correlation (r) | 0.924 | 0.934 |
| P-value (ANOVA) | 0.494 | 0.346 |
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Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not specified in the provided text, only referred to as "clinical samples."
- Data Provenance: Not specified in the provided text. It is unclear if it's retrospective or prospective or the country of origin.
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Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
- Not applicable. The study compares the new device to existing legally marketed predicate devices, not against expert-established ground truth for diagnosis/classification.
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Adjudication Method for the Test Set:
- Not applicable. The study is a comparative performance study against predicate devices, not one requiring adjudication of diagnostic outcomes.
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Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, a MRMC study was not done. The study compares the performance of the new device against predicate devices using quantitative measurements of Protein S levels.
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Standalone Performance (Algorithm only without human-in-the-loop performance):
- Yes, this is a standalone performance study. The REAADS Protein S Antigen Test Kit is an in vitro diagnostic assay that produces quantitative results directly. Human intervention is involved in conducting the assay and interpreting the results in a clinical context, but the performance evaluation here specifically focuses on the accuracy of the assay itself in determining Protein S levels compared to existing methods.
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Type of Ground Truth Used:
- The "ground truth" for this study is the results obtained from legally marketed predicate devices: the Helena Protein S Antigen Rocket EID Method and the Helena Free Protein S Reagent. The study aims to demonstrate substantial equivalence to these established methods.
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Sample Size for the Training Set:
- Not applicable. This is not a machine learning model, so there is no "training set." The device is a laboratory assay.
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How the Ground Truth for the Training Set Was Established:
- Not applicable, as there is no training set for this type of device.
§ 864.7290 Factor deficiency test.
(a)
Identification. A factor deficiency test is a device used to diagnose specific coagulation defects, to monitor certain types of therapy, to detect coagulation inhibitors, and to detect a carrier state (a person carrying both a recessive gene for a coagulation factor deficiency such as hemophilia and the corresponding normal gene).(b)
Classification. Class II (performance standards).