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ID
Source
Brief title
Health condition
Antiphospholipid syndrome, thrombosis
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary objective of this study is to determine discrepancies between INR measurements with Coaguchek and Coagulometer in lupus anticoagulant positive APS patients.
Secondary outcome
The secondary objective of this study is to investigate which antiphospholipid antibodies correlate with the found INR discrepancies. Furthermore, we will look into the differences within two different groups of APS patients: triple positive APS patients (tested positive for at least lupus anticoagulant, anti-cardiolipin antibodies and anti-β2-glycoprotein I antibodies) and non-triple positive patients (tested positive for at least lupus anticoagulant).
Background summary
Antiphospholipid syndrome (APS) is characterized by recurrent thrombosis or pregnancy complications in patients with persistent antiphospholipid antibodies. Patients with APS receive anticoagulant therapy with vitamin K antagonists (VKA) to prevent recurrent thrombosis. VKA treatment can be monitored with the international normalized ratio (INR), which is based on clotting tests. The optimal therapeutic window for VKA is an INR between 2.0 and 3.0. An INR < 2.0 is associated with an increased risk of thrombosis and an INR > 3.0 is associated with an increased risk of bleeding. Frequent monitoring and, if necessary, VKA dose adaptation, ensures patients receive adequate anticoagulation. Whilst the INR is routinely measured with clotting tests in a diagnostic laboratory, many patients monitor their own INR with Point Of Care (POC) devices. However, antiphospholipid antibodies can interfere with clotting reactions. Whereas INR reagents used in diagnostic laboratories are insensitive for interference by antiphospholipid antibodies, there are indications that reagents in POC devices are not, which could lead to false INR values and inadequate anticoagulation.
In the current study, we will investigate whether INR values in APS patients measured with the most commonly used POC device in the Netherlands (CoaguChek XS) are similar to the gold standard method used in the UMC Utrecht diagnostic laboratory; the Owren method based on a rabbit brain-derived thromboplastin.
Study objective
We expect differences in INR values between the CoaguCHek and Coagulometer in lupus anticoagulant positive APS patients.
Study design
1x venepuncture and 1x finger stick per patient
Intervention
Patients will endure 1 finger stick procedure and 1 venepuncture,
Inclusion criteria
In order to be eligible to participate in this study, a subject must meet all of the following criteria:
- Age 18 years and older
- Previously confirmed APS, diagnosed in accordance with the Sydney criteria22
- Receiving VKA during at least 3 months
- Willing and be able to understand the study information and sign the informed consent form
Exclusion criteria
A potential subject who meets any of the following criteria will be excluded from participation in this study:
- None
Design
Recruitment
IPD sharing statement
Followed up by the following (possibly more current) registration
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Other (possibly less up-to-date) registrations in this register
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In other registers
| Register | ID |
|---|---|
| NTR-new | NL9427 |
| Other | METC Utrecht : 21-139 |