Point of Care Testing INR in Antiphospholipid Syndrome (POCTAS)

Explaining the Differences Between Capillary INR and Plasma INR in Patients With Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune and prothrombotic disorder that can affect up to 10% of young people experiencing a thrombotic event. Its treatment relies on long-term anticoagulation with vitamin K antagonists (VKAs). Direct oral anticoagulants, which are simpler to use because they do not require regular blood monitoring, are contraindicated because they are associated with an increased risk of thrombotic recurrence in some patients with APS.

Patients with APS receive VKAs and must regularly have their Index Normalized Ratio (INR) measured via a cumbersome venous blood draw. Capillary INR measurement systems are already used in certain situations, such as in patients with mechanical heart valves. The use of these systems improves the quality of life of these patients and, above all, the stability of VKA therapy, thus preventing potentially serious hemorrhagic complications or thrombotic recurrences.

In antiphospholipid syndrome (APS), these systems are discouraged due to perceived differences between capillary and venous INR (the reference method). However, among the few studies on the subject, none demonstrated significant discrepancies between patients with APS and controls, and when such discrepancies were observed, the origin of this variability could not be determined. We hypothesize that the biological profile of antiphospholipid antibodies is responsible for the INR differences.

Study Overview

• Status: Not yet recruiting
• Conditions: Antiphospholipid Syndrome; Vitamine K Antagonist (VKA) Treatment
• Intervention / Treatment: Device: Coaguchek

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Stéphane ZUILY, MD, PhD; Phone Number: +33 03 83 15 73 54; Email: stephane.zuily@univ-lorraine.fr

Study Locations

• France
  • Vandœuvre-lès-Nancy, France, 54500
    • CHRU de Nancy
    • Sub-Investigator: Denis Wahl, MD, PhD
    • Principal Investigator: Stéphane Zuily, MD, PhD
    • Contact: Aurélie Emmerich; Phone Number: +33 03 83 15 36 14; Email: a.emmerich@chru-nancy.Fr
    • Sub-Investigator: Virginie Dufrost, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with APS treated with vitamin K antagonists (VKAs)

  • Patients with an LA profile without aCL or anti-β2GPI (isolated LA)
  • Patients with an LA and aCL + anti-β2GPI profile (triple positivity)
  • Patients with another biological profile (other than isolated LA or triple positivity)
• Control patients without aCL or anti-β2GPI treated with VKAs
• Adult patients
• Patients who have undergone a prior clinical examination appropriate for the research
• Individuals who have received complete information on the organization of the research and have not objected to their participation and the use of their data
• Patients covered by a social security scheme

Exclusion Criteria:

• Patients with antiphospholipid syndrome (APS) not treated with vitamin K antagonists (VKAs)
• Women of childbearing age without effective contraception

• Persons covered by Articles L. 1121-5, L. 1121-7, and L. 1121-8 of the French Public Health Code:

  • Pregnant, parturient, or breastfeeding women
  • Unemancipated minors
  • Adults under legal protection (guardianship, curatorship, or protective supervision)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Lupus Anticoagulant positive patients; Patients with isolated Lupus Anticoagulant positive test only	Device: Coaguchek; Point of care testing INR using Coaguchek device
Experimental: Triple positive patients; Patients with triple positivity of antiphospholipid tests	Device: Coaguchek; Point of care testing INR using Coaguchek device
Experimental: Other antiphospholipid profile patients; Patients with another aPL profile other than isolated LAC or triple positivity	Device: Coaguchek; Point of care testing INR using Coaguchek device
Active Comparator: No antiphospholipid; Patients with no antiphospholipid antibodies	Device: Coaguchek; Point of care testing INR using Coaguchek device

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Discrepancy between Coaguchek and venous INR	Percentage of patients per group with a fixed 20% discrepancy between a capillary INR measured on a Coagucheck© device and a venous INR according to subgroups and variables	At enrollment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Discrepancy between MicroLine and venous INR	Percentage of patients per group with a fixed 20% discrepancy between a capillary INR measured on a MicroLine INR© device and a venous INR according to subgroups and variables	At enrollment
Discrepancy between Coaguchek and MicroLine INR	Percentage of patients per group with a fixed 20% discrepancy between a capillary INR measured on a Coagucheck© and MicroLine devices according to subgroups and variables	At enrollment

Collaborators and Investigators

• Sponsor: Central Hospital, Nancy, France

Publications and helpful links

Helpful Links

• ISTH subcommittee website

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: April 30, 2026
• First Submitted That Met QC Criteria: April 30, 2026
• First Posted (Actual): May 6, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: INR; vitamin K; Antiphospholipid
• Additional Relevant MeSH Terms: Autoimmune Diseases; Immune System Diseases; Antiphospholipid Syndrome
• Other Study ID Numbers: 2024-A01316-41

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No