(90 days)
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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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: a symbol on the left and the FDA name on the right. The symbol on the left is a stylized image of a human figure, while the FDA name on the right is written in blue letters. The words "U.S. FOOD & DRUG ADMINISTRATION" are written in a clear, sans-serif font.
January 28, 2025
Instrumentation Laboratory (IL) Co. Nikita Malladi Regulatory Affairs Manager II 180 Hartwell Rd Bedford, Massachusetts 01730
Re: K243374
Trade/Device Name: HemosIL CL HIT-IgG(PF4-H) Regulation Number: 21 CFR 864.7695 Regulation Name: Platelet Factor 4 Radioimmunoassay Regulatory Class: Class II Product Code: LCO Dated: October 30, 2024 Received: October 30, 2024
Dear Nikita Malladi:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
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2
(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30. Design controls; 21 CFR 820.90. Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the OS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rue"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advicecomprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
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Sincerely,
YAN CÀI S
for
Min Wu, Ph.D. Branch Chief Division of Immunology and Hematology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known)
Device Name HemosIL CL HIT-IgG(PF4-H)
Indications for Use (Describe)
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 etther positive 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 HT. For use in adult population suspected of HIT. Not for use in isolation to exclude HIT.
For prescription use only.
| Type of Use (Select one or both, as applicable) |
|---|
| ------------------------------------------------- |
X Prescription Use (Part 21 CFR 801 Subpart D)
| Over-The-Counter Use (21 CFR 801 Subpart C)
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Image /page/4/Picture/0 description: The image shows the word "werfen" in a bold, sans-serif font. The color of the text is a dark blue. The letters are evenly spaced and the word is horizontally oriented.
510(k) Summary
This 510(k) Summary of Safety and Effectiveness is being submitted in accordance with the requirements of 21 CFR 807.92.
| 510(k) Submitter | Instrumentation Laboratory (IL) Company180 Hartwell RoadBedford, MA 01730-2443 (USA)Establishment Registration: 1217183 | Chemiluminescent Assay | Device Description | ||
|---|---|---|---|---|---|
| Primary Contact | Nikita MalladiRegulatory Affairs Manager IIPhone: 781-353-1486Fax: 781-861-4207Email: nmalladi@werfen.com | HemosIL CL HIT IgG(PF4-H) | HemosIL CL HIT-IgG(PF4-H) assay is a chemiluminescent two-step immunoassayconsisting 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 theparticles. After a second incubation, magnetic separation, and a wash step, reagents thattrigger the luminescent reaction are added, and the emitted light is measured as relativelight units (RLUs) by the ACL TOP 970 CL optical system. The RLUs are directlyproportional to the PF4/H IgG concentration in the sample. | ||
| Preparation Date | October 30, 2024 | 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 andlot dependent and it is stored in the instrument through the cartridge barcode. With themeasurement of calibrators, the predefined Master Curve is transformed to a new,instrument specific 4PLC Working Curve. The concentration values of the calibratorsare included in the reagent kit calibrator value sheet 2D barcode. | |||
| Device Trade Name | HemosIL CL HIT-IgG(PF4-H) | Intended Use / Indication for Use | |||
| Predicate Devicesand 510(k) Number | HemosIL AcuStar HIT-IgG(PF4-H) | K170854 | HemosIL CL HIT-IgG(PF4-H) is a qualitative, fully automated, chemiluminescentimmunoassay (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 plasmaon the ACL TOP 970 CL in a laboratory setting. | ||
| Regulatory Information | Chemiluminescent Assay | The result provided by the assay should be interpreted as either positive or negativebased on the assay cut-off (1.00 U/mL). The positive or negative result aids indetermining the risk for heparin induced thrombocytopenia (HIT) when used inconjunction with other laboratory and clinical findings. | |||
| HemosIL CL HIT-IgG(PF4-H) | Classification | Class II | Anti-PF4/heparin antibodies are commonly found in patients with HIT. For use withadult population suspected of HIT. Not for use in isolation to exclude HIT. | ||
| HemosIL CL HIT-IgG(PF4-H) | Classification Panel | Hematology (81) | For prescription use only. | ||
| HemosIL CL HIT-IgG(PF4-H) | Regulation Section No. | 21 CFR 864.7695 | |||
| HemosIL CL HIT-IgG(PF4-H) | Regulation Description | Platelet factor 4radioimmunoassay | |||
| HemosIL CL HIT-IgG(PF4-H) | Product Code | LCO |
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| HemosIL CL HIT-IgG(PF4-H) Comparison to Predicate Device | ||
|---|---|---|
| Item | Predicate Device (K170854) | New Device |
| Trade Names | HemosIL AcuStar HIT-IgG(PF4-H) | HemosIL CL HIT-IgG(PF4-H) |
| Manufacturer | Instrumentation Laboratory Co. | Same |
| Measurand | Anti-PF4/Heparin IgG Antibodies | Same |
| Assay Type | Qualitative | Same |
| Product Code | LCO | Same |
| Regulation Section | 21 CFR 864.7695 | Same |
| Classification | Class II | Same |
| Intended Use | HemosIL AcuStar HIT-IgG(PF4-H) is aqualitative, fully automated, chemiluminescentimmunoassay (CIA) for the detection of IgGantibodies that react with Platelet Factor 4(PF4) when complexed to heparin. The assay isfor use in human 3.2% or 3.8% citrated plasmaand serum on the ACL AcuStar instrument in alaboratory setting.The result provided by the assay should beinterpreted as either positive or negative basedon the assay cut-off (1.00 U/mL). The positiveor negative result aids in determining the riskfor heparin induced thrombocytopenia (HIT)when used in conjunction with other laboratoryand clinical findings.Anti-PF4/Heparin antibodies are commonlyfound in patients with HIT. For use in adultpopulation suspected of HIT. Not for use inisolation to exclude HIT.For prescription use. | HemosIL CL HIT-IgG(PF4-H) is a qualitative, fullyautomated, chemiluminescent immunoassay (CIA) forthe detection of IgG antibodies that react with PlateletFactor 4 (PF4) when complexed to heparin. The assay isfor use in human 3.2% citrated plasma on the ACL TOP970 CL in a laboratory setting.The result provided by the assay should be interpreted aseither positive or negative based on the assay cut-off(1.00 U/mL). The positive or negative result aids indetermining the risk for heparin inducedthrombocytopenia (HIT) when used in conjunction withother laboratory and clinical findings.Anti-PF4/heparin antibodies are commonly found inpatients with HIT. For use with adult populationsuspected of HIT. Not for use in isolation to excludeHIT.For prescription use only. |
| HemosIL CL HIT-IgG(PF4-H) Comparison to Predicate Device (Cont.) | ||
| Item | Predicate Device (K170854) | New Device |
| Methodology | Chemiluminescent immunoassay (CIA) | Same |
| Reagents | Cartridge containing magnetic particlesuspension coated with PF4 complexed topolyvinyl sulfonate (PVS) | Same |
| Antibodies | Mouse monoclonal anti-human IgG antibody | Same |
| Conjugate | Isoluminol conjugated anti-human IgG | Same |
| Cut-off | Fixed clinical cut-off:• Positive: $\ge$ 1.00 U/mL• Negative: $\lt$ 1.00 U/mL | Same |
| Composition | 1 cartridge containing 1 vial of magneticparticle suspension coated with PF4/PVScomplex, 1 vial of assay buffer, 1 vial of tracerconsisting of an mAb anti-human IgG antibodylabeled with isoluminol, and 1 vial of samplediluent used for the regular predilution of thesample. The reagents are in a phosphate or Trisbuffer containing bovine serum albumin,bovine fetal serum, PF4/PVS complex, mousemonoclonal IgG, stabilizers, and preservative. | 1 cartridge containing 1 vial of magnetic particlesuspension coated with PF4/PVS complex, 1 vial ofassay buffer, 1 vial of tracer consisting of an mAbanti-human IgG antibody labeled with isoluminol,and 1 vial of sample diluent used for the regularpredilution of the sample. The reagents are in aphosphate or HEPES buffer containing bovineserum albumin, bovine fetal serum, PF4/PVScomplex, mouse monoclonal IgG, stabilizers, andpreservative. |
| Calibrators | Two calibrator levels (included in the kit):• Calibrator 1 target value: 1.00 U/mL• Calibrator 2 target value: 16.00 U/mLLiquid format | Two calibrator levels (included in the kit):• Calibrator 1 target value: 1.00 U/mL• Calibrator 2 target value: 16.50 U/mLLiquid format |
| Controls | Two control levels (sold separately):• Low Control target value: 0.60 U/mL• High Control target value: 3.00 U/mLLiquid format | Two control levels (sold separately):• Low Control target value: 0.60 U/mL• High Control target value: 3.50 U/mLLiquid format |
| Sample Type | Human citrated plasma or serum | Human 3.2% citrated plasma |
| Instrumentation | ACL AcuStar | ACL TOP 970 CL |
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Precision
HemosIL CL HIT-IgG(PF4-H)
A precision study was performed in accordance with CLSI EPU5-A3 (3" Edition), using three lots of HET-IgGrew, reagent. Repeatability and within laboratory precision were assessed. To span the study tested 5 plasma samples and 2 levels of HemosIL CL Multi-Ab Controls and 3 lots of HemosIL CL Multi-Ab Controls (low and high). Each material was run in duplicate, twice per day over 20 days on an ACL TOP 970 CL.
The tables below show data for 1 representative reagent lot and also aggregated data for the 3 reagent lots.
| ACL TOP 970 CL | Mean (U/mL) | Repeatability (% CV) | Within Laboratory (% CV) |
|---|---|---|---|
| Low CL Multi-Ab Control | 0.446 | 5.2 | 7.4 |
| High CL Multi-Ab Control | 3.231 | 3.0 | 5.9 |
| Plasma Sample A (Pool) | 0.248 | 8.2 | 10.7 |
| Plasma Sample B (Pool) | 0.907 | 2.9 | 5.7 |
| Plasma Sample C (Pool) | 1.346 | 3.1 | 6.5 |
| Plasma Sample D (Unadulterated) | 1.910 | 3.4 | 6.3 |
| Plasma Sample E (Pool) | 19.677 | 2.6 | 6.0 |
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| Performance Characteristics: New HemosIL CL Reagent (Cont.) | |||||||
|---|---|---|---|---|---|---|---|
| Precision (Cont.) | |||||||
| HemosIL CL HIT-IgG(PF4-H) | |||||||
| Aggregated data (Reagent Lots 1, 2, and 3) | |||||||
| Material | Mean (U/mL) | Lot-to-Lot Variability (% CV) | |||||
| Low CL Multi-Ab Control | 0.440 | 2.1 | |||||
| High CL Multi-Ab Control | 3.260 | 2.0 | |||||
| Plasma Sample A | 0.272 | 8.1 | |||||
| Plasma Sample B | 0.777 | 14.5 | |||||
| Plasma Sample C | 1.210 | 9.7 | |||||
| Plasma Sample D | 1.817 | 4.5 | |||||
| Plasma Sample E | 21.451 | 9.5 |
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Reproducibility
HemosIL CL HIT-IgG(PF4-H)
Reproducibility studies were contucted at 3 extenal cliferent operators (1 operator per site), on 3 different ACL TOP 970 CL system (1 system per site), using 3 lots of HemosIL CL HIT-IgGyerin To span the same 6 plasma samples were tested across the 3 sites, with the HemosIL CL Multi-Ab Controls.
Each level for all materials was tested across 3 sites twice per day over 5 days with 3 replicates for each of the 3 reagent lots.
The pooled data for a representative reagent lot is presented below.
| Level | Mean(U/mL) | N | Repeatability | Between-run | Between-day | Between-site | Between-lot | Reproducibility(Total) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SD | % CV | SD | % CV | SD | % CV | SD | % CV | SD | % CV | SD | % CV | |||||
| Low CL Multi-Ab Control | 0.515 | 270 | 0.0212 | 4.1 | 0.0241 | 4.7 | 0.0000 | 0.0 | 0.0195 | 3.8 | 0.0107 | 2.1 | 0.0390 | 7.6 | ||
| High CL Multi-Ab Control | 3.487 | 270 | 0.1047 | 3.0 | 0.1214 | 3.5 | 0.0530 | 1.5 | 0.0464 | 1.3 | 0.0803 | 2.3 | 0.1926 | 5.5 | ||
| Plasma Sample1 (Pool) | 0.405 | 270 | 0.0521 | 12.9 | 0.0050 | 1.2 | 0.0098 | 2.4 | 0.0242 | 6.0 | 0.0000 | 0.0 | 0.0585 | 14.4 | ||
| Plasma Sample 2(Unadulterated) | 0.050 | 270 | All Replicates < 1.00 U/mL | |||||||||||||
| Plasma Sample 3(Pool) | 0.845 | 270 | 0.0509 | 6.0 | 0.0228 | 2.7 | 0.0255 | 3.0 | 0.0201 | 2.4 | 0.0000 | 0.0 | 0.0645 | 7.6 | ||
| Plasma Sample 4(Pool) | 1.336 | 270 | 0.0813 | 6.1 | 0.0423 | 3.2 | 0.0000 | 0.0 | 0.0327 | 2.4 | 0.0250 | 1.9 | 0.1005 | 7.5 | ||
| Plasma Sample 5(Pool) | 2.622 | 270 | 0.1015 | 3.9 | 0.0569 | 2.2 | 0.0505 | 1.9 | 0.0322 | 1.2 | 0.0960 | 3.7 | 0.1623 | 6.2 | ||
| Plasma Sample 6(Pool) | 19.082 | 270 | 0.6650 | 3.5 | 0.4223 | 2.2 | 0.3153 | 1.7 | 0.8525 | 4.5 | 2.8821 | 15.1 | 3.1230 | 16.4 |
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Analytical Sensitivity
Limit of detection (LoD) was assessed per CLSI EP17-A2 (2nd Edition) using three different lots of HemosIL CL HIT-IgGream reagent cartridges. Based on the results, the limit of blank (LoB) is 0.09 U/mL and the limit of detection (LoD) is 0.14 U/mL.
Linearity
Linearity was not applicable to this HemosIL CL HIT-IgGpp4-m submission.
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Analytical Specificity
Interference testing was performed in accordance with CLSI EP07 (3ª Edition) using HemosIL CL HIT-IgG(PF4-H) reagent cartridge.
Based on the results, following are the interference claims for the new chemiluminescent assay:
No interference for:
| ● | Hemoglobin | 1000 mg/dL |
|---|---|---|
| ● | Bilirubin (unconjugated) | 40 mg/dL |
| ● | Bilirubin (conjugated) | 40 mg/dL |
| ● | Triglycerides | 1500 mg/dL |
| ● | Unfractionated heparin | 1.2 IU/mL |
| ● | Low molecular weight heparin | 2.5 IU/mL |
| ● | Human anti-mouse antibodies (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 |
Twenty four citrated plasma samples from patients diagnosed with Antiphospholipid Syndrome (APS) were tested with the HemosIL CL HIT-IgGream assay and four commercially available antiphospholipid antibody assays (anticardiolipin IgG, anti-cardiolipin IgM, anti-ß2 glycoprotein I IgG, anti-B2 glycoprotein I IgM). Three out of the twenty four samples recovered above the cut-off of 1.00 U/mL for HemosIL CL HIT-IgG(er4.h. These three samples also tested positive for anti-cardiolipin IgG but tested negative for thee antiphospholipid assays.
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Normal Reference Range
A normal range study was performed in accordance with CLSI EP28-A3c (3th Edition) using two lots of HemosIL CL HIT-IgGreen reagent cartridge. The normal range was verified on the ACL TOP 970 CL. The threshold for positive HIT-IgG antibodies were established in the 90th percentile.
Cut-Off Validation: A method comparison with the Serotonin Release Assay (SRA) on 91 citrated plasma samples from HIT suspected patients (45 SRA positive and 46 SRA negative) validated a cut-off value of 1.00 UmL (98.9% Agreement, 95% CI = 94.0% - 99.8%; 97.8% Negative Percent Agreement, 95% CI = 88.7% - 99.6%, 100.0% Positive Percent Agreement, 95% CI = 92.1% - 100.0%).
Following are the resultant upper limits of the normal range for the heparin exposed and healthy donors:
| Reference Interval | ||
|---|---|---|
| Patient Population | No. of CitratedPlasma Samples | Upper Limit |
| Heparin Exposed, Non-HIT Suspected Patients | 132 | 1.42 U/mL |
| Healthy Donors | 122 | 0.45 U/mL |
Based on these studies it has been determined that for heparin treated patient samples, HemosIL CL HIT-IgQyP4+H results equal to or higher than 1.00 U/mL may indicate the presence of anti-PF4/H antibodies.
Method Comparison
An external, multicenter method comparison study was performed at three clinical sites comparing HemosIL CL HIT-IgGeren with HemosIL AcuStar HIT-IgGream. The samples were from HIT-suspected patients. The results summarized below are based on a cut-off value of 1.00 U/mL for the HemosIL CL HIT-IgGregun assay and the HemosIL AcuStar HIT-IgG(PF4-H) assay.
| HemosIL AcuStar HIT-IgG(PF4-H) Results | ||||
|---|---|---|---|---|
| + | - | Total | ||
| HemosIL CL HIT-IgG(PF4-H) Results | + | 91 | 1 | 92 |
| - | 3 | 246 | 249 | |
| Total | 94 | 247 | 341 | |
| Proportion | Wilson 95% CI | |||
| PPA (Positive Percent Agreement) | 97% (91/94) | 91% | 99% | |
| NPA (Negative Percent Agreement) | 100% (246/247) | 98% | 100% | |
| Total Percent Agreement | 99% (337/341) | 97% | 100% |
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Conclusion
Based on the substantial equivalence comparison and the results of the conducted performance evaluations, the HemosIL CL HIT-IgGpy.cn assay on the ACL TOP 970 CL was shown to be substantially equivalent to the cleared and currently marketed device, HemosIL AcuStar HIT-IgGrev-m ( K170854) on the ACL AcuStar (K083518). The differences between the subject and predicate devices do not impact safety and effectiveness.
§ 864.7695 Platelet factor 4 radioimmunoassay.
(a)
Identification. A platelet factor 4 radioimmunoassay is a device used to measure the level of platelet factor 4, a protein released during platelet activation by radioimmunoassay. This device measures platelet activiation, which may indicate a coagulation disorder, such as myocardial infarction or coronary artery disease.(b)
Classification. Class II (performance standards).