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510(k) Data Aggregation
(90 days)
HemosIL CL HIT-IgG(PF4-H)
HemosIL CL HIT-IgG(PF4-H) is a qualitative, fully automated, chemiluminescent immunoassay (CIA) for the detection of IgG antibodies that react with Platelet Factor 4 (PF4) when complexed to heparin. The assay is for use in human 3.2% citrated plasma on the ACL TOP 970 CL in a laboratory setting.
The result provided by the assay should be interpreted as either positive or negative based on the assay cut-off (1.00 U/mL). The positive or negative result aids in determining the risk for heparin induced thrombocytopenia (HIT) when used in conjunction with other laboratory and clinical findings.
Anti-PF4/Heparin antibodies are commonly found in patients with HIT. For use in adult population suspected of HIT. Not for use in isolation to exclude HIT.
For prescription use only.
HemosIL CL HIT-IgG(PF4-H) assay is a chemiluminescent two-step immunoassay consisting of magnetic particles coated with PF4 complexed to polyvinyl sulfonate (PVS) which capture, if present, PF4/H antibodies from the sample. After incubation, magnetic separation, and a wash step, a tracer consisting of an isoluminol-labeled anti-human IgG antibody is added and may bind with the captured PF4/H IgG on the particles. After a second incubation, magnetic separation, and a wash step, reagents that trigger the luminescent reaction are added, and the emitted light is measured as relative light units (RLUs) by the ACL TOP 970 CL optical system. The RLUs are directly proportional to the PF4/H IgG concentration in the sample.
The HemosIL CL HIT-IgG(PF4-H) assay utilizes a 4 Parameter Logistic Curve fit (4PLC) data reduction method to generate a Master Curve. The Master Curve is predefined and lot dependent and it is stored in the instrument through the cartridge barcode. With the measurement of calibrators, the predefined Master Curve is transformed to a new, instrument specific 4PLC Working Curve. The concentration values of the calibrators are included in the reagent kit calibrator value sheet 2D barcode.
Here's a breakdown of the acceptance criteria and study information for the HemosIL CL HIT-IgG(PF4-H) device, based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Characteristic | Acceptance Criteria (Implicit) | Reported Device Performance (HemosIL CL HIT-IgG(PF4-H)) |
|---|---|---|
| Precision | As demonstrated by predicate | Repeatability (%CV): Controls 3.0-5.2%, Samples 2.6-8.2% |
| Within-Laboratory (%CV): Controls 5.9-7.4%, Samples 5.7-10.7% | ||
| Lot-to-Lot Variability | As demonstrated by predicate | Controls 2.0-2.1%, Samples 4.5-14.5% |
| Reproducibility | As demonstrated by predicate | Total Reproducibility (%CV): Controls 5.5-7.6%, Samples 6.2-16.4% (for measurable samples) |
| Analytical Sensitivity | As demonstrated by predicate | LoB: 0.09 U/mL, LoD: 0.14 U/mL |
| Analytical Specificity | No interference at specified concentrations | No interference for: Hemoglobin (1000 mg/dL), Bilirubin (unconjugated & conjugated 40 mg/dL), Triglycerides (1500 mg/dL), Unfractionated heparin (1.2 IU/mL), LMWH (2.5 IU/mL), HAMA (1 µg/mL), Rheumatoid Factor (160 IU/mL), Acid citric dextrose (0.45 g/dL), Argatroban (1.2 µg/mL), Fondaparinux (0.102 mg/dL), Dabigatran (0.900 mg/dL), Rivaroxaban (0.270 mg/dL), Protamine (5 mg/dL) |
| Method Comparison (vs. Predicate) | High agreement (e.g., >95%) | PPA: 97% (91/94), NPA: 100% (246/247), Total Agreement: 99% (337/341) |
| Cut-Off Validation (vs SRA) | High agreement (e.g., >95%) | 98.9% Agreement, 97.8% Negative Percent Agreement, 100.0% Positive Percent Agreement |
| Normal Reference Range | Established values | Heparin Exposed, Non-HIT Suspected Patients: Upper Limit 1.42 U/mL (n=132); Healthy Donors: Upper Limit 0.45 U/mL (n=122) |
| Intended Use | Consistent with predicate | Maintained qualitative detection of IgG antibodies to PF4-heparin complexes in 3.2% citrated plasma for adult HIT suspicion. |
2. Sample Size Used for the Test Set and Data Provenance
- Precision Study: 5 plasma samples and 2 levels of controls. Tested over 20 days.
- Reproducibility Study: 6 plasma samples. Tested across 3 external sites, twice per day over 5 days with 3 replicates.
- Analytical Sensitivity (LoD): Not explicitly stated, but assessed using "three different lots" of reagent cartridges.
- Analytical Specificity: Not explicitly stated, but involved testing with various interfering substances and 24 citrated plasma samples from APS patients.
- Normal Reference Range Study: 132 Heparin-Exposed, Non-HIT Suspected Patients and 122 Healthy Donors.
- Cut-Off Validation Study (vs. SRA): 91 citrated plasma samples (45 SRA positive, 46 SRA negative).
- Method Comparison Study (vs. Predicate): 341 samples from HIT-suspected patients.
Data Provenance: The document does not explicitly state the country of origin for the patient data. It is implied to be retrospective as the samples were "from HIT-suspected patients" or "patients diagnosed with Antiphospholipid Syndrome (APS)", suggesting they were pre-collected. The reproducibility study explicitly states it was done at "3 external" sites.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number or qualifications of experts used to establish the ground truth for the test set.
- For the Cut-Off Validation Study, Serotonin Release Assay (SRA) results were used as the reference standard, indicating a highly specialized laboratory assay.
- For the Method Comparison Study, the predicate device (HemosIL AcuStar HIT-IgG(PF4-H)) served as the reference standard.
- For the Normal Reference Range Study, patient classification as "Heparin Exposed, Non-HIT Suspected Patients" or "Healthy Donors" implies a clinical determination, but no expert involvement is specifically detailed.
4. Adjudication Method for the Test Set
The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for the test set or for establishing ground truth. The SRA and predicate device results appear to be taken as the reference.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (IVD) immunoassay, not an imaging or software device that would typically involve human readers. The study focuses on the analytical and clinical performance of the assay itself.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done
Yes, the studies described are standalone performance evaluations of the HemosIL CL HIT-IgG(PF4-H) assay. The device is a "fully automated, chemiluminescent immunoassay (CIA)" and the performance data reflects its direct measurement capabilities on an ACL TOP 970 CL instrument without explicit human-in-the-loop interpretation beyond standard laboratory procedures for running the assay and reporting results. The device provides a qualitative positive or negative result based on a cut-off.
7. The Type of Ground Truth Used
The types of ground truth used include:
- Serotonin Release Assay (SRA): For the cut-off validation study, which is considered a gold standard for HIT diagnosis.
- Predicate Device Results (HemosIL AcuStar HIT-IgG(PF4-H)): For the method comparison study, establishing equivalence to a previously cleared device.
- Clinical Diagnosis/Patient Classification: For the normal reference range study (e.g., "Heparin Exposed, Non-HIT Suspected Patients" and "Healthy Donors") and sample collection for methodology studies (e.g., "HIT-suspected patients", "patients diagnosed with Antiphospholipid Syndrome (APS)").
8. The Sample Size for the Training Set
The document does not explicitly describe a separate "training set" for the device. As an IVD immunoassay, the development process typically involves internal optimization and validation studies, but these are not usually structured as a distinct "training set" in the same way as machine learning algorithms. The mentioned studies are primarily for performance validation and substantial equivalence claims. A "Master Curve" is generated for the assay, which is "predefined and lot dependent" and stored in the instrument, indicating calibration and internal standardization but not a "training set" in the common sense for AI/ML.
9. How the Ground Truth for the Training Set Was Established
Since an explicit "training set" in the context of AI/ML is not described, the method for establishing its ground truth is not applicable. The "Master Curve" concept implies calibration and validation using known standards and controls, which are part of the assay's design and manufacturing process.
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