(252 days)
Serotonin Release Assay (SRA)
No
The device description and performance studies focus on a standard immunoassay technology and statistical analysis of results, with no mention of AI or ML algorithms for data processing, interpretation, or decision support.
No.
This device is an in vitro diagnostic (IVD) intended to detect antibodies related to heparin-induced thrombocytopenia (HIT), which aids in diagnosis and risk assessment, rather than providing direct therapy.
Yes
Explanation: The "Intended Use / Indications for Use" section explicitly states that the assay "aids in determining the risk for heparin induced thrombocytopenia (HIT) when used in conjunction with other laboratory and clinical findings," which is a diagnostic purpose.
No
The device is a laboratory immunoassay kit that includes physical reagents (latex particles, buffers, complex, calibrator, controls) and is used on specific hardware instruments (ACL TOP® Family). It is not solely software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The "Intended Use / Indications for Use" section explicitly states that the assay is for use in human plasma to detect anti-platelet factor 4/heparin antibodies. This is a diagnostic test performed on a biological sample outside of the body.
- Laboratory Setting: The assay is intended for use "in a laboratory setting." This is a common characteristic of IVDs.
- Diagnostic Aid: The results "aid in determining the risk for heparin induced thrombocytopenia (HIT) when used in conjunction with other laboratory and clinical findings." This clearly indicates a diagnostic purpose.
- Device Description: The description details a "latex particle enhanced immuno-turbidimetric assay" which is a method used for in vitro diagnostic testing.
- Controls and Calibrators: The kit includes controls and a calibrator, which are essential components for ensuring the accuracy and reliability of an in vitro diagnostic test.
- Performance Studies: The document includes detailed performance studies (precision, reproducibility, method comparison, interference, etc.) which are required for demonstrating the analytical and clinical performance of an IVD.
- Predicate Device: A predicate device (Asserachrom HPIA Test kit) is mentioned, which is a common reference point for demonstrating substantial equivalence for IVDs.
- Reference Device: A reference device (Serotonin Release Assay - SRA) is also mentioned, which is a gold standard or highly regarded method used for comparison in IVD validation.
All of these elements strongly indicate that the HemosIL HIT-Ab(PF4-H) is an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
HemosIL HIT-Ab(PF4-H) is a qualitative, fully automated, latex enhanced immunoassay for the detection of anti-platelet factor 4/heparin (PF4/H) antibodies. The assay is for use in human 3.2% or 3.8% citrated plasma on the ACL TOP® Family of instruments in a laboratory setting.
The result provided by the assay should be interpreted as either positive or negative based on the assay cut-off (1.0 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.
HemosIL HIT-Ab(PF4-H) Controls are for the Quality Control of the HemosIL HIT-Ab(PF4-H) assay as performed on the ACL TOP Family of instruments.
For prescription use.
Product codes (comma separated list FDA assigned to the subject device)
LCO, GGN
Device Description
The HemosIL HIT-Ab(PF4-H) kit is a latex particle enhanced immuno-turbidimetric assay to detect total Anti-PF4/Heparin (PF4/H) antibodies found in HIT patients. A monoclonal antibody that mimics human HIT antibodies is coated onto latex particles.
In the presence of PF4 from human platelets complexed to polyvinyl sulfonate (PVS), and the patient sample, a competitive agglutination reaction occurs.
The degree of agglutination is inversely proportional to the concentration of antibodies in the sample and is determined by measuring the decrease of transmitted light caused by the aggregates.
The HemosIL HIT- Ab(PF4-H) kit consists of:
Latex Reagent: Suspension of polystyrene latex particles coated with purified mouse monoclonal anti-PF4-Heparin in Tris buffer, containing bovine serum albumin, stabilizers and preservative.
Stabilizer: PBS buffer containing bovine serum albumin, stabilizers and preservative.
Complex: Solution of PF4-PVS complex (PF4 from human platelets complexed to PVS), in PBS buffer containing bovine serum albumin, stabilizers and preservative. Contains 0.02% Bronidox™ as a preservative.
Calibrator: Lyophilized solution of a monoclonal anti- PF4-Heparin antibody in Tris buffer containing bovine serum albumin, stabilizers and preservative.
Controls: The Low and High HIT-Ab(PF4-H) Controls are prepared by means of a dedicated process and contain different concentrations of humanized monoclonal anti-PF4-Heparin-human IgG.
Low HIT-Ab(PF4-H) Control: Control intended for the assessment of precision and accuracy of the assay at PF4/H antibody levels at or below the cut-off.
High HIT-Ab(PF4-H) Control: Control intended for the assessment of precision and accuracy of the assay at abnormal PF4/H antibody levels.
Use of both controls is recommended for a complete quality control program.
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
Not Found
Indicated Patient Age Range
adult population
Intended User / Care Setting
laboratory setting
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
An internal precision study was performed using three (3) different lots of HemosIL HIT-Ab(PF4-H) reagents run on a representative ACL TOP Family member (ACL TOP 700). The study used a single lot of HemosL HIT-Ab(PF4-H) Controls (low and high), as well as five (5) patient pools prepared at different levels to span the assay range. Each material was tested with each reagent lot in duplicate, twice a day for 20 days, for a total of 80 replicates per level per lot.
Reproducibility studies were conducted at three (3) external clinical sites by three (3) different operators (one operator per site), on three (3) different ACL TOP 500 CTS instrument per site), using three (3) different lots of HemosIL HIT-Ab(PF4-H) reagents and HemosIL HIT-Ab(PF4-H) Controls (low and high). To span the assay range, three (3) patient pools (2 positive) and a manufactured material containing a citrated plasma sample spiked with monoclonal anti-PF4-Heparin antibody were also tested (Plasma Sample 4). Each material was tested in triplicate, twice a day for 5 days, for a total of 30 replicates per level.
An internal precision study was performed using three (3) different lots of HemosIL HIT-Ab(PF4-H) Controls (low and high) run on a representative ACL TOP Family member (ACL TOP 700), with a single lot of HemoslL HIT-Ab(pf4-h) reagents. Each level of control material from each lot was tested in duplicate, twice a day for 20 days, for a total of 80 replicates per level per lot.
Reproducibility studies were conducted at three external clinical sites using different operators, on three different ACL TOP 500 CTS instruments, using three different lots of HemoslL HIT-Abperay, reagents and HemosIL HIT-Abperen Controls (low and high). Each material was tested in triplicate, twice a day for 5 days, for a total of 30 replicates per level.
An internal precision study was performed using three (3) different lots of HemoslL HIT-Ab(PF4-H) Calibrator (kit component from 3 different reagent lots) run on a representative ACL TOP Family member (ACL TOP 700), with a single lot of HemosIL HIT-Ablere-m reagents (with a different kit Calibrator lot). Each calibrator lot was tested in duplicate, twice a day for 20 days, for a total of 80 replicates per lot.
An internal unadulterated (unmodified) patient plasma study was performed on a representative ACL TOP Family member (ACL TOP 700). The two (2) patient samples used in the study were collected at a hospital in the United States, with aliquots prepared and maintained at -70°C until use. Each sample aliguot was tested in duplicate, twice a day for 10 days, for a total of 40 replicates per patient plasma sample.
An instrument model equivalency study was performed using fifty-one (51) citrated plasma samples from individual clinical patients who were suspected of having HIT. Each clinical sample was analyzed in singlicate with a single lot of HemosIL HIT-Ab(PF4-H) reagents on representative ACL TOP Family members: ACL TOP 700, ACL TOP 500 CTS and ACL TOP 300 CTS.
A linearity study was performed using two (2) lots of HemosIL HIT-Ab(PF4-H) reagents, with each lot tested on three (3) representative ACL TOP Family members: ACL TOP 500 CTS and ACL TOP 300 CTS. Two (2) positive patient samples were spiked into donor plasma from a blood bank to prepare 10 concentrations ranging across the standard measurement range (0.6-5.7 U/mL). A third extremely high positive patient sample was used to prepare samples with concentrations ranging across the auto re-run linear range (2.1 to 16.0 U/mL).
One hundred twenty-six (126) citrated plasma samples from non-HIT suspected, heparin treated patients (either UFH or LMWH) were tested with the HemosIL HIT-Abperin assay. For LMWH, 115 samples with a heparin concentration range between 0-2.47 IU/mL. For UFH, 11 samples with a heparin concentration range between 0.04-1.08 IU/mL.
Forty (40) citrated plasma samples from patients who were diagnosed with Antiphospholipid Syndrome (APS) were tested with the HemosIL HIT-Ab(PF4-H) assay.
A population of one hundred thirty-one (131) citrated plasma samples from apparently healthy individuals was tested with the HemosIL HIT-Ab(PF4-H) assay.
A population of one hundred twenty-two (122) citrated plasma samples from HIT-suspected, but negative by a commercially available ELISA was tested with the HemosIL HIT-Ab(PF4-H) assay.
Sixty three (63) citrated plasma samples were obtained from hospitalized patients who had been exposed to heparin, and who displayed clinical signs consistent with Heparin Induced Thrombocytopenia (HIT). These patients were tested by the hospital with the Serotonin Release Assay (SRA) and the sample results (31 SRA positive and 32 SRA negative) were used to perform a Receiver Operating Characteristics (ROC) analysis to determine the clinical cut-off for HemosIL HIT-Ablpp4-H).
An internal method comparison study was performed to compare the performance of the new Hemos L HIT-Ab(PF4-H) assay versus its predicate, the Asserachrom HPIA Test Kit (K003767), on a representative member of the ACL TOP Family (ACL TOP 700 model). A total of 118 frozen citrated patient plasma samples from patients referred for HIT testing were obtained from a hospital in the US and a hospital in France. Samples were analyzed in singlicate, with no spiked samples used in this study.
A multicenter method comparison study was conducted at three (3) hospitals on 632 patient samples, comparing the performance of the new HemosIL HIT-Aber4-with the predicate device, the Asserachrom HPIA Test Kit (K003767) and with the reference device, Serotonin Release Assay (SRA). The samples were from patients exposed to heparin who showed HIT related symptoms. Samples were analyzed in singlicate, with no spiked samples used in this study.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Multi-Reagent Lot Precision:
- Study type: Internal precision study over 20 days.
- Sample size: Five (5) patient pools and two controls. Total 80 replicates per level per lot.
- Key results: %CV for controls ranged from 2.6% to 9.9% (Within Run) and 3.3% to 9.9% (Total). For plasma samples, %CV ranged from 2.3% to 10.6% (Within Run) and 3.6% to 13.5% (Total). Lot-to-lot variability for controls and plasma samples ranged from 3.7% to 7.2% for aggregated data.
Multi-Reagent Lot Site-to-Site Reproducibility:
- Study type: External clinical reproducibility study over 5 days.
- Sample size: Two controls and four patient/manufactured materials. Total 30 replicates per level per site.
- Key results: Total reproducibility %CV across three sites for Reagent Lot 1 ranged from 6.1% to 15.3%. For Reagent Lot 2, it ranged from 2.3% to 8.1%. For Reagent Lot 3, it ranged from 5.5% to 11.0%. Plasma Sample 1 consistently showed all replicates
§ 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).
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
July 08, 2016
Instrumentation Laboratory (IL) Co. Ms. Carol Marble Regulatory Affairs Director 180 Hartwell Road Bedford. MA 01730
Re: K153137
Trade/Device Name: HemosIL HIT-Ab(PF4-H); HemosIL HIT-Ab(PF4-H) Controls Regulation Number: 21 CFR 864.7695 Regulation Name: Platelet factor 4 radioimmunoassay Regulatory Class: Class II Product Code: LCO, GGN Dated: June 6, 2016 Received: June 8, 2016
Dear Ms. Marble:
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 (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. 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.
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
1
CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours.
Leonthena R. Carrington -S
Leonthena R. Carrington, MS, MBA, MT(ASCP) Director Division of Immunology and Hematology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
2
Indications for Use
510(k) Number (if known) K153137
Device Name HemosIL HIT-Ab(PF4-H) HemosIL HIT- Ab(PF4-H) Controls
Indications for Use (Describe)
HemosIL HIT-Ab(PF4-H) is a qualitative, fully automated, latex enhanced immunoassay for the detection of anti-platelet factor 4/heparin (PF4/H) antibodies. The assay is for use in human 3.2% or 3.8% citrated plasma on the ACL TOP® Family of instruments in a laboratory setting.
The result provided by the assay should be interpreted as either positive based on the assay cut-off (1.0 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.
HemosIL HIT-Ab(PF4-H) Controls are for the Quality Control of the HemosIL HIT-Ab(PF4-H) assay as performed on the ACL TOP® Family of instruments.
For prescription use.
| Type of Use (Select one or both, as applicable) | |
|---|---|
| ☑ Prescription Use (Part 21 CFR 801 Subpart D) | □ Over-The-Counter Use (21 CFR 801 Subpart C) |
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Image /page/3/Picture/0 description: The image shows the logo for Instrumentation Laboratory, which is a Werfen Company. The logo features a stylized graphic element composed of two overlapping shapes in shades of green and blue. To the right of the graphic is the company name, "Instrumentation Laboratory," stacked on two lines in a sans-serif font. Below the company name is the tagline "A Werfen Company" in a smaller font size.
510(k) Summary
This 510(k) Summary of Safety and Effectiveness is being submitted in accordance with the requirements of the Safe Medical Device Act of 1990 and 21 CFR 807.92.
| Submitter's Information | Instrumentation Laboratory (IL) Co. | ||
|---|---|---|---|
| 180 Hartwell Road | |||
| Bedford, MA 01730, USA | |||
| Contact Person | Carol Marble, Regulatory Affairs Director | ||
| Phone: 781-861-4467 | |||
| Fax: 781-861-4207 | |||
| Email: cmarble@ilww.com | |||
| Preparation Date | June 28, 2016 | ||
| Device Trade Names | Reagent Kit (with Calibrator) | HemosIL HIT-Ab(PF4-H) | |
| Controls | HemosIL HIT-Ab(PF4-H) Controls | ||
| Regulatory Information - | |||
| Reagent Kit | Regulation Number | 21 CFR 864.7695 | |
| Regulation Description | Platelet Factor 4 Radioimmunoassay | ||
| Classification | Class II | ||
| Product Code | LCO | ||
| Classification Panel | Hematology (81) | ||
| Regulatory Information - | |||
| Controls | Regulation Number | 21 CFR 864.5425 | |
| Regulation Description | Plasma, Coagulation Control | ||
| Classification | Class II | ||
| Product Code | GGN | ||
| Classification Panel | Hematology (81) | ||
| Predicate Device | K003767 (Asserachrom HPIA Test kit from Diagnostica Stago) |
4
| Indications for Use /
Intended Use | HemosIL HIT-Ab(PF4-H) is a qualitative, fully automated, latex enhanced
immunoassay for the detection of anti-platelet factor 4/heparin (PF4/H)
antibodies. The assay is for use in human 3.2% or 3.8% citrated plasma on
the ACL TOP® Family of instruments in a laboratory setting.
The result provided by the assay should be interpreted as either positive or
negative based on the assay cut-off (1.0 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.
HemosIL HIT-Ab(PF4-H) Controls are for the Quality Control of the HemosIL
HIT-Ab(PF4-H) assay as performed on the ACL TOP Family of instruments.
For prescription use. |
|------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Device Description
Reagent Kit with
Calibrator | The HemosIL HIT-Ab(PF4-H) kit is a latex particle enhanced immuno-
turbidimetric assay to detect total Anti-PF4/Heparin (PF4/H) antibodies
found in HIT patients. A monoclonal antibody that mimics human HIT
antibodies is coated onto latex particles.
In the presence of PF4 from human platelets complexed to polyvinyl
sulfonate (PVS), and the patient sample, a competitive agglutination
reaction occurs.
The degree of agglutination is inversely proportional to the concentration
of antibodies in the sample and is determined by measuring the decrease
of transmitted light caused by the aggregates.
The HemosIL HIT- Ab(PF4-H) kit consists of:
[Image: R]
Latex Reagent: Suspension of polystyrene latex particles coated with
purified mouse monoclonal anti-PF4-Heparin in Tris buffer,
containing bovine serum albumin, stabilizers and preservative.
[Image: S]
Stabilizer: PBS buffer containing bovine serum albumin, stabilizers
and preservative.
[Image: Com]
Complex: Solution of PF4-PVS complex (PF4 from human platelets
complexed to PVS), in PBS buffer containing bovine serum albumin,
stabilizers and preservative. Contains 0.02% Bronidox™ as a
preservative.
[Image: C]
Calibrator: Lyophilized solution of a monoclonal anti- PF4-Heparin
antibody in Tris buffer containing bovine serum albumin, stabilizers
and preservative. |
| Controls | The Low and High HIT-Ab(PF4-H) Controls are prepared by means of a
dedicated process and contain different concentrations of humanized
monoclonal anti-PF4-Heparin-human IgG.
Low HIT-Ab(PF4-H) Control: Control intended for the assessment of precision
and accuracy of the assay at PF4/H antibody levels at or below the cut-off.
High HIT-Ab(PF4-H) Control: Control intended for the assessment of precision
and accuracy of the assay at abnormal PF4/H antibody levels.
Use of both controls is recommended for a complete quality control
program. |
5
| Comparison to Predicate | ||
|---|---|---|
| Item | Predicate | New Device |
| Trade Names | Asserachrom HPIA Test Kit | |
| (Kit Includes 2 Control Levels) | HemosIL HIT-Ab(PF4-H) | |
| HemosIL HIT-Ab(PF4-H) Controls | ||
| Manufacturer | Diagnostica Stago | Instrumentation Laboratory Co. |
| Similarities | ||
| Measurand | Anti-PF4/Heparin Total Antibodies | Same |
| Assay Type | Qualitative | Same |
| Detection Method | Absorbance (Colorimetric) | Absorbance (Turbidimetric) |
| Product Code | LCO | Same |
| Regulation Section | 864.7695 | Same |
| Classification | Class II | Same |
| Intended Use | The ASSERACHROM® HPIA Test Kit is | |
| intended for use as a qualitative | ||
| procedure for the detection of anti- | ||
| heparin-platelet factor 4 (anti- | ||
| Heparin-PF4) antibodies in citrated | ||
| plasma or serum by the sandwich | ||
| technique of enzyme-linked | ||
| immunosorbent assay (ELISA). |
The presence in plasma or serum of
anti-Heparin-PF4 antibodies,
together with a concurrent drop in
platelet count, is generally
associated with Type II heparin-
induced thrombocytopenia (Type II
HIT), a condition that occurs during
heparin therapy, leading to arterial
or venous thrombosis. | HemosIL HIT-Ab(PF4-H) is a qualitative,
fully automated, latex enhanced
immunoassay for the detection of anti-
platelet factor 4/heparin (PF4/H)
antibodies. The assay is for use in
human 3.2% or 3.8% citrated plasma
on the ACL TOP® Family of instruments
in a laboratory setting.
The result provided by the assay should
be interpreted as either positive or
negative based on the assay cut-off
(1.0 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.
HemosIL HIT-Ab(PF4-H) Controls are for
the Quality Control of the HemosIL HIT-
Ab(PF4-H) assay as performed on the ACL
TOP Family of instruments.
For prescription use. |
| Differences | | |
| Methodology | Two-step enzyme immunoassay
(ELISA) sandwich method with a
final colorimetric detection. | Latex-enhanced immuno-
turbidimetric assay. |
| Sample Types | Citrated Human Plasma or Serum | Citrated Human Plasma Only |
| Antibodies | Goat anti-human antibodies to
IgG, IgA and IgM | Purified mouse monoclonal
anti-PF4-Heparin |
| Cut-off | Variable clinical cut-off
Cut-off is lot and plate dependent.
Every time a plate is processed, the
cut-off for this plate is calculated as
the percentage (X%) of the value
obtained for the Reagent 6 supplied
with the kit. This percentage is
provided for each lot through the
insert sheets. | Fixed clinical cut-off: ≥ 1.0 U/mL |
| Controls | Controls included in test kit:
• Negative level
• Positive level | Controls sold separately:
• Low Level at or below the cut-off
• High Level at abnormal
anti-PF4/H antibody level. |
| Calibrator Traceability | Not Applicable | The reported values for the kit
calibrator are determined over
multiple runs on the ACL TOP Family
of instruments using specific lots of
reagents and against an internal
House Standard. Since a HIT
International Standard is not
currently available, Arbitrary Units
(U/ml) have been established. |
6
7
Performance Summary
Multi-Reagent Lot Precision
An internal precision study was performed using three (3) different lots of HemosIL HIT-Ab(PF4-H) reagents run on a representative ACL TOP Family member (ACL TOP 700). The study used a single lot of HemosL HIT-Ab(PF4-H) Controls (low and high), as well as five (5) patient pools prepared at different levels to span the assay range. Each material was tested with each reagent lot in duplicate, twice a day for 20 days, for a total of 80 replicates per level per lot as summarized below:
| Reagent Lot No. 1 | |||
|---|---|---|---|
| Material | Mean | ||
| (U/mL) | Within Run (Repeatability) | ||
| % CV | Total (Within Device) | ||
| % CV | |||
| Low HIT-Ab(PF4-H) Control | 0.8 | 9.0 | 9.9 |
| High HIT-Ab(PF4-H) Control | 2.5 | 2.6 | 3.3 |
| Plasma Sample 1 | 0.8 | 10.6 | 13.5 |
| Plasma Sample 2 | 1.5 | 3.8 | 4.3 |
| Plasma Sample 3 | 3.3 | 3.0 | 4.5 |
| Plasma Sample 4 | 9.2 | 3.0 | 3.8 |
| Plasma Sample 5 | 15.3 | 3.4 | 4.3 |
| Reagent Lot No. 2 | |||
| Material | Mean | ||
| (U/mL) | Within Run (Repeatability) | ||
| % CV | Total (Within Device) | ||
| % CV | |||
| Low HIT-Ab(PF4-H) Control | 0.7 | 7.9 | 9.3 |
| High HIT-Ab(PF4-H) Control | 2.5 | 3.1 | 3.9 |
| Plasma Sample 1 | 0.8 | 9.0 | 11.1 |
| Plasma Sample 2 | 1.5 | 3.9 | 4.4 |
| Plasma Sample 3 | 3.4 | 7.2 | 7.2 |
| Plasma Sample 4 | 8.8 | 2.9 | 3.6 |
| Plasma Sample 5 | 14.7 | 4.8 | 5.3 |
| Reagent Lot No. 3 | |||
| Material | Mean | ||
| (U/mL) | Within Run (Repeatability) | ||
| % CV | Total (Within Device) | ||
| % CV | |||
| Low HIT-Ab(PF4-H) Control | 0.7 | 8.4 | 9.9 |
| High HIT-Ab(PF4-H) Control | 2.3 | 3.5 | 4.0 |
| Plasma Sample 1 | 0.7 | 10.1 | 10.2 |
| Plasma Sample 2 | 1.4 | 3.8 | 4.7 |
| Plasma Sample 3 | 3.0 | 4.4 | 5.9 |
| Plasma Sample 4 | 8.3 | 2.3 | 3.8 |
| Plasma Sample 5 | 13.3 | 3.2 | 4.3 |
8
| Aggregated data (Reagent Lots 1, 2 and 3) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Material | Mean | |||||||||
| (U/mL) | Lot-to-Lot Variability | |||||||||
| %CV | ||||||||||
| Low HIT-Ab(PF4-H) Control | 0.7 | 4.1 | ||||||||
| High HIT-Ab(PF4-H) Control | 2.4 | 3.7 | ||||||||
| Plasma Sample 1 | 0.8 | 5.2 | ||||||||
| Plasma Sample 2 | 1.5 | 6.3 | ||||||||
| Plasma Sample 3 | 3.3 | 6.1 | ||||||||
| Plasma Sample 4 | 8.8 | 5.3 | ||||||||
| Plasma Sample 5 | 14.4 | 7.2 |
Multi-Reagent Lot Site-to-Site Reproducibility
Reproducibility studies were conducted at three (3) external clinical sites by three (3) different operators (one operator per site), on three (3) different ACL TOP 500 CTS instrument per site), using three (3) different lots of HemosIL HIT-Ab(PF4-H) reagents and HemosIL HIT-Ab(PF4-H) Controls (low and high). To span the assay range, three (3) patient pools (2 positive) and a manufactured material containing a citrated plasma sample spiked with monoclonal anti-PF4-Heparin antibody were also tested (Plasma Sample 4)
Each material was tested in triplicate, twice a day for 5 days, for a total of 30 replicates per level.
The pooled data for each reagent lot are summarized below and on the next page:
| Pooled 3-Site Data: Reagent Lot 1 of HemosIL HIT-Ab(PF4-H) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Level | Mean | Repeatability | |||||||||
| (within-run) | Between-Run | Between-Day | Between Site | Reproducibility | |||||||
| (Total) | |||||||||||
| (U/mL) | SD | % CV | SD | % CV | SD | % CV | SD | %CV | SD | % CV | |
| Low HIT-Ab(PF4-H) Control | 0.9 | 0.11 | 11.7 | 0.07 | 7.1 | 0.00 | 0.0 | 0.06 | 6.7 | 0.14 | 15.3 |
| High HIT-Ab(PF4-H) Control | 2.6 | 0.13 | 5.1 | 0.06 | 2.1 | 0.07 | 2.7 | 0.00 | 0.0 | 0.16 | 6.1 |
| Plasma Sample 2 | 2.1 | 0.11 | 5.2 | 0.08 | 3.9 | 0.00 | 0.0 | 0.05 | 2.2 | 0.14 | 6.8 |
| Plasma Sample 3 | 4.0 | 0.21 | 5.2 | 0.05 | 1.2 | 0.12 | 2.9 | 0.00 | 0.0 | 0.25 | 6.1 |
| Plasma Sample 4 | 13.4 | 0.88 | 6.5 | 0.00 | 0.0 | 0.33 | 2.5 | 0.73 | 5.5 | 1.19 | 8.9 |
| Level | Mean | ||||||||||
| (U/mL) | Result | ||||||||||
| Plasma Sample 1 | 0.4 | All Replicates TP | True Positives | ||||||||
| + | TP | FP | TN | True Negatives | |||||||
| Test | - | FN | TN | FP | False Positives | ||||||
| FN | False Negatives | ||||||||||
| Positive Percent Agreement | |||||||||||
| Negative Percent Agreement | $PPA = \frac{TP}{TP + FN}$ | $NPA = \frac{TN}{TN + FP}$ |
| Negative Predictive Value | $PPV = \frac{TP}{TP + FP}$ | $NPV = \frac{TN}{TN + FN}$ |
|---|---|---|
| Positive Predictive Value |
$$\textbf{TPA} \qquad \textbf{Total PercentAgreement} \qquad \qquad TPA \quad = \frac{TP + TN}{TP + TN + FP + FN}$$
Method Comparison (Internal)
An internal method comparison study was performed to compare the performance of the new Hemos L HIT-Ab(PF4-H) assay versus its predicate, the Asserachrom HPIA Test Kit (K003767), on a representative member of the ACL TOP Family (ACL TOP 700 model).
A total of 118 frozen citrated patient plasma samples from patients referred for HIT testing were obtained from a hospital in the US and a hospital in France. Samples were analyzed in singlicate, with no spiked samples used in this study.
The results summarized below are based on a cut-off of 1.0 U/mL for the HemosIL HIT-Ab(PF4-H) assay and the lot- and plate-dependent cut-off for the Asserachrom HPIA Test Kit.
PPA NPA
NPV
PPV
14
| HPIA ELISA results | ||||
|---|---|---|---|---|
| + | - | Total | ||
| HemosIL HIT-Ab(PF4-H) | ||||
| results | + | 68 | 8 | 76 |
| - | 13 | 29 | 42 | |
| Total | 81 | 37 | 118 |
| HemosIL HIT-Ab(PF4-H) vs Asserachrom HPIA | Proportion | Wilson 95% CI | |
|---|---|---|---|
| PPA (Positive Percent Agreement) | 84% (68/81) | 74% | 91% |
| NPA (Negative Percent Agreement) | 78% (29/37) | 62% | 90% |
| Total Percent Agreement | 82% (97/118) | 74% | 89% |
Multicenter Method Comparison
A multicenter method comparison study was conducted at three (3) hospitals on 632 patient samples, comparing the performance of the new HemosIL HIT-Aber4-with the predicate device, the Asserachrom HPIA Test Kit (K003767) and with the reference device, Serotonin Release Assay (SRA). The samples were from patients exposed to heparin who showed HIT related symptoms. Samples were analyzed in singlicate, with no spiked samples used in this study.
HemosIL HIT-Ab(PF4-H) Assay vs. Predicate Device (Asserachrom HPIA Test Kit)
The pooled results below are based on a cut-off of 1.0 U/mL for the HemosIL HIT-Ab(PF4-H) assay and the lotand plate-dependent cut-off for the Asserachrom HPIA Test Kit.
| HPIA ELISA results | ||||
|---|---|---|---|---|
| + | - | Total | ||
| HemosIL HIT-Ab(PF4-H) | ||||
| results | + | 67 | 39 | 106 |
| - | 22 | 504 | 526 | |
| Total | 89 | 543 | 632 |
| HemosIL HIT-Ab(PF4-H) vs Asserachrom HPIA | Proportion | Wilson 95% CI | |
|---|---|---|---|
| PPA (Positive Percent Agreement) | 75% (67/89) | 65% | 83% |
| NPA (Negative Percent Agreement) | 93% (504/543) | 90% | 95% |
| Total Percent Agreement | 90% (571/632) | 88% | 92% |
15
HemosIL HIT-Ab(PF4-H) Assay vs. SRA and Predicate vs. SRA
Patient samples in the multicenter study without a valid SRA result or with an indeterminate result (total N=95) were removed from calculations, bringing the final total to N = 537.
The pooled results summarized below compare both HemosIL HIT-Ab(PF4-H) assay results (cut-off of 1.0 U/mL) to the SRA test results and the Asserachrom HPIA Test Kit (lot- and plate-dependent cut-off) to the SRA test results.
- HemosIL HIT-Ab(PF4-H) Assay vs. SRA:
| SRA Results | ||||
|---|---|---|---|---|
| + | - | Total | ||
| HemosIL HIT-Ab(PF4-H) | ||||
| results | + | 33 | 56 | 89 |
| - | 59 | 389 | 448 | |
| Total | 92 | 445 | 537 |
| HemosIL HIT-Ab(PF4-H) vs SRA | Proportion | Wilson 95% CI |
|---|---|---|
| PPV (Positive Predictive Value) | 37% (33/89) | 28% 47% |
| NPV (Negative Predictive Value) | 87% (389/448) | 83% 90% |
- Asserachrom HPIA Test Kit (Predicate) vs. SRA: ●
| SRA Results | ||||
|---|---|---|---|---|
| + | - | Total | ||
| HPIA ELISA results | + | 31 | 37 | 68 |
| - | 61 | 408 | ||
| Total | 92 | 445 |
| Asserachrom HPIA vs SRA | Proportion | Wilson 95% CI |
|---|---|---|
| PPV (Positive Predictive Value) | 46% (31/68) | 34% 57% |
| NPV (Negative Predictive Value) | 87% (408/469) | 84% 90% |
Conclusion: The diagnostic performance of the HemosIL HIT-Ab(PF4-H) assay was equivalent to the Asserachrom HPIA Test Kit (predicate) when compared to SRA test results.
16
HemosIL HIT-Ablprach Assay vs. 2013 American Society of Hematology (ASH) Guidelines
The results summarized below are based on the 2013 ASH guideline for determining clinical probability. The ASH diagnostic algorithm classifies samples as HIT Likely or HIT Unlikely based on a clinical probability score (i.e. patient 4T score), the Asserachrom HPIA Test Kit (as the ELISA result) and the SRA results (as the functional assay). In this retrospective study using the multicenter data, the results of the ASH diagnostic algorithm were compared with the data obtained with HemosIL HIT-Ab(PF4-H).
NOTE: The performance results are not based on a confirmed diagnosis of HIT.
| | | Clinical Probability
According to 2013 ASH | | |
|----------------------------------|-------|-----------------------------------------------|--------------|-------|
| | | HIT Likely | HIT Unlikely | Total |
| HemosIL HIT-Ab(PF4-H)
results | + | 17 | 72 | 89 |
| | - | 2 | 446 | 448 |
| | Total | 19 | 518 | 537 |
| Clinical Probability according to ASH 2013 | Proportion | Wilson 95% CI | |
|---|---|---|---|
| PPA (Positive Percent Agreement) | 89% (17/19) | 69% | 97% |
| NPA (Negative Percent Agreement) | 86% (446/518) | 83% | 89% |
| Clinical Probability according to ASH 2013 | Proportion | Wilson 95% CI | |
|---|---|---|---|
| PPV (Positive Predictive Value) | 19% (17/89) | 12% | 28% |
| NPV (Negative Predictive Value) | 100% (446/448) | 98% | 100% |
Conclusion:
The analytical and clinical study results demonstrate that the HemosIL HIT-Ab(PF4-H) assay and HemosIL HIT-Ab(PF4-H) Controls are substantially equivalent to the predicate device, Asserachrom HPIA Test Kit (FDA cleared under K003767), and that the assay is safe and effective for its labeled intended use when compared to the SRA reference method.