(98 days)
The Heparin/Platelet Factor 4 Antibody Serum Panel is an assayed control, intended for use as a serum QC control to monitor and evaluate precision and accuracy of the (qualitative) PIFA® Heparin/PF4 Antibody Assay. Included are both confirmed positive and negative control panel members.
The panel members enable the users to evaluate their PIFA® Heparin/PF4 Antibody Assay test systems and provide comprehensive data for comparative analysis.
The Heparin/Platelet Factor 4 Antibody Serum Panel is a well-qualified serum sample identified as a positive or negative sample against the PIFA® Heparin/Platelet Factor 4 Antibody Assay. The panels are assembled from its repository of frozen serum samples, with reactivity as determined by the (FDA cleared) GTT® PF4 ENHANCED® ELISA Assay test currently available within the United States. No preservatives are added. Samples are chosen to provide a broad range of reactivity and to include samples with low antibody levels and samples with high antibody levels. A "positive" identified serum panel has OD values greater than 0.400 as determined on the GTT® PF4 ENHANCED® ELISA Assay test.
Two types of kit configurations are available, specifically for use on the PIFA ® Heparin/Platelet Factor 4 Antibody Assay test systems: 2 Member QC Panel (1 positive and 1 negative sera) and Multi-Member Qualification Panel (either a 12-Member (10 positive and 2 negative sera) or 6-Member (5 positive and 1 negative sera)). All panel member vials each contain approximately 150 ul in total volume.
Here's an analysis of the acceptance criteria and study information provided for the Heparin/Platelet Factor 4 Antibody Serum Panel:
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" in a numerical or target performance metric for the device itself. Instead, it describes the expected consistent performance of the control panel members when tested with the PIFA® Heparin/Platelet Factor 4 Rapid Assay and correlation with the GTT® PF4 ENHANCED® ELISA Assay. The performance is reported in terms of reproducibility and precision.
Here's a table summarizing the reported device performance in relation to what can be inferred as expected outcomes:
| Performance Metric | Expected Outcome (Implied Acceptance Criteria) | Reported Device Performance |
|---|---|---|
| Reproducibility | Consistent expected results with PIFA® assay across freeze-thaw cycles. | PIFA® H/PF4 Rapid Assay vs. GTI® PF4 ENHANCED® Value: |
| Positive: 40 (correctly positive) | ||
| Negative: 20 (correctly negative) | ||
| (No false positives or negatives reported) | ||
| Precision | Consistent expected results with PIFA® assay across multiple formats/runs. | PIFA® H/PF4 Rapid Assay vs. GTI® PF4 ENHANCED® ELISA Assay Value: |
| Positive: 30 (correctly positive) | ||
| Negative: 20 (correctly negative) | ||
| (No false positives or negatives reported) | ||
| Stability (via freeze-thaw) | Maintain characterization (positive/negative) through freeze-thaw cycles. | Panel members consistently produced expected results and correlated with O.D. values from the GTT® PF4 ENHANCED® ELISA assay after varying freeze-thaw cycles. |
| Correlation | Results consistently correlate with O.D. values from the GTT® PF4 ENHANCED® ELISA assay. | Results consistently correlate with the O.D. values from the GTT® PF4 ENHANCED® ELISA assay for both reproducibility and precision studies. |
Note on "Acceptance Criteria": The document focuses more on demonstrating the consistency and stability of the control panels, rather than setting specific quantitative acceptance thresholds for accuracy or sensitivity/specificity of the control panels themselves. The "acceptance" is implied by the consistent and expected categorization (positive/negative) of the control samples.
2. Sample Size Used for the Test Set and Data Provenance
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Reproducibility Study (Study #1):
- Sample Size: 40 positive samples and 20 negative samples were tested repeatedly. (Total = 60 distinct samples, each tested in duplicate over 5 days through varying freeze-thaw cycles).
- Data Provenance: Not explicitly stated, but the testing was performed "internally" and/or by an "independent laboratory." There is no mention of country of origin of the data. The study design ("repetition of the testing procedure utilizing the PIFA® Heparin/Platelet Factor 4 Rapid Assay in conjunction with the GTT® PF4 ENHANCED® ELISA Assay") suggests a controlled lab setting.
- Retrospective/Prospective: Not explicitly stated, but the studies describe active testing being performed, suggesting a prospective design from the perspective of generating the performance data for the panels. The repository of frozen serum samples from which the panels are assembled would likely be existing (retrospective collection), but the testing itself is prospective.
-
Precision Study (Study #2):
- Sample Size: 30 positive samples and 20 negative samples were tested. (Total = 50 distinct samples, each tested in multiple formats.)
- Data Provenance: Same as Reproducibility Study – "internally" and/or "independent laboratory", no country of origin, likely prospective testing on existing samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The ground truth for the test set (the characterization of the control samples as "positive" or "negative") was established using the FDA cleared GTT® PF4 ENHANCED® ELISA Assay.
- Number of Experts: Not applicable in the context of human experts.
- Qualifications of Experts: Not applicable. The ground truth relies on the performance of a previously cleared, predicate assay.
- The document states: "A 'positive' identified serum panel has OD values greater than 0.400 as determined on the GTT® PF4 ENHANCED® ELISA Assay test." This establishes the objective criterion for ground truth.
4. Adjudication Method for the Test Set
Not applicable. The ground truth was established by an objective assay (GTT® PF4 ENHANCED® ELISA Assay) with a clear optical density (OD) cutoff, not through expert adjudication.
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 assayed control panel, not an AI diagnostic device that assists human readers.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
This is not an algorithm or AI device. It is a physical control panel. The performance described is the standalone performance of the control panel itself when used with the PIFA® Heparin/Platelet Factor 4 Rapid Assay, and its correlation with the predicate GTT® PF4 ENHANCED® ELISA Assay.
7. The Type of Ground Truth Used
The ground truth used for characterizing the control panel members (determining if they are "positive" or "negative") was based on the performance of a predicate, FDA-cleared laboratory assay (GTT® PF4 ENHANCED® ELISA Assay) with objective quantitative cutoff values (OD > 0.400 for positive).
8. The Sample Size for the Training Set
The concept of a "training set" is not directly applicable here in the machine learning sense. The panels are assembled from a repository of frozen serum samples, but the document does not specify the total size of this repository or how many samples were used for "training" in the sense of developing the panel characteristics. The samples chosen for the panels "provide a broad range of reactivity and to include samples with low antibody levels and samples with high antibody levels," implying selection criteria rather than an algorithmic training process.
9. How the Ground Truth for the Training Set Was Established
Similarly to the test set, the characterization of the samples within the repository (and thus, for any "training" or selection process for the panels) would have been established by determining their reactivity using the GTT® PF4 ENHANCED® ELISA Assay. The document states that the reactivity was "as determined by the (FDA cleared) GTT® PF4 ENHANCED® ELISA Assay test."
§ 864.5425 Multipurpose system for in vitro coagulation studies.
(a)
Identification. A multipurpose system for in vitro coagulation studies is a device consisting of one automated or semiautomated instrument and its associated reagents and controls. The system is used to perform a series of coagulation studies and coagulation factor assays.(b)
Classification. Class II (special controls). A control intended for use with a multipurpose system for in vitro coagulation studies is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 864.9.