(104 days)
GTI-FVIII Inhibitor Assay is designed as a solid phase Enzyme-Linked Immunosorbent Assay (ELISA). The product is intended to be used as an in vitro diagnostic kit by hemostasis and other laboratories providing factor VIII inhibitor assay to assist in screening samples for the presence of alloantibodies to epitopes on FVIII molecule.
FVIII Inhibitor Assay is an ELISA platform which is designed to detect IgG antibodies to human recombinant FVIII in human plasma samples. Recombinant human FVIII molecules are passively immobilized in microtiter wells. Patient plasma is tested against wells containing immobilized recombinant FVIII and compared to the reaction obtained from the negative control sera included in the kit. The results are obtained in optical density (OD) values. The patient samples having OD values greater than the cutoff value are regarded as being positive.
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria (Implied) | Reported Device Performance (GTI-FVIII Inhibitor Assay) |
|---|---|
| Detects FVIII antibodies with high concordance to Bethesda assay | Concordance: 89.6% |
| Detects FVIII antibodies with high sensitivity compared to Bethesda assay | Sensitivity: 98.9% |
| Detects FVIII antibodies with high negative predictive value compared to Bethesda assay | Negative Predictive Value: 98.8% |
| Lot-to-lot consistency | Comparable between three different lots |
| Tech-to-tech consistency | Good correlation of results obtained by three different individuals |
| Stability over dating period | Stable over a 27-month period |
2. Sample size used for the test set and the data provenance
The sample size for the test set is not explicitly stated in the provided text.
The data provenance is retrospective, comparing the GTI-FVIII Inhibitor Assay to the Bethesda assay in previously collected samples. The country of origin is not specified, but the study was conducted in "two independent clinical laboratories."
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. The Bethesda assay is used as the reference standard (ground truth), but the number and qualifications of experts involved in performing or interpreting the Bethesda assay results are not detailed.
4. Adjudication method for the test set
Not explicitly stated. Given that the comparison is against the Bethesda assay, it's implied that the Bethesda assay results served as the reference without a separate adjudication process for the test set itself beyond what is inherent in the Bethesda assay's methodology.
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
No, an MRMC comparative effectiveness study was not done. The study compares the performance of a device (ELISA kit) to a predicate assay, not the performance of human readers with or without AI assistance.
6. If a standalone (i.e. algorithm only, without human-in-the-loop performance) was done
Yes, a standalone study was done. The reported performance (concordance, sensitivity, negative predictive value) is for the GTI-FVIII Inhibitor Assay device itself, without human interpretation as part of the primary outcome measure. The device provides "optical density (OD) values" which are then compared to a cutoff value to determine positive or negative results. While human technical staff operate the ELISA, the interpretation of the results as positive or negative is algorithm-driven based on the OD values.
7. The type of ground truth used
The type of ground truth used is a reference assay/methodology, specifically the Bethesda assay.
8. The sample size for the training set
The text does not mention a separate training set. The study describes the comparison of the GTI-FVIII Inhibitor Assay to the Bethesda assay, implying a validation or test set, but no distinct training set for developing the device is detailed in this summary.
9. How the ground truth for the training set was established
Not applicable, as a separate training set and its ground truth establishment are not discussed in the provided summary. The device's underlying principles (ELISA platform detecting IgG antibodies to FVIII) suggest it was developed based on established immunological assays, but the specifics of its internal development and training (if any, in a machine learning sense) are not provided.
§ 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).