NCT00878137

Reliability of Point-of-care INR Measurements in Patients With Antiphospholipid-antibody Syndrome Treated With Warfarin

INR Determined by Plasma-based Methods Versus Newer Point-of-care Instruments in Patients With Antiphospholipid-antibody Syndrome Treated With Anticoagulants

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 63 (actual)
• Sponsor: University of North Carolina, Chapel Hill · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The antiphospholipid-antibody syndrome (APLA), which includes lupus anticoagulant, anticardiolipin, and anti-beta-2-glycoproteinI antibodies, is a thrombophilic disorder associated with arterial thrombosis, venous thrombosis or both. Patients diagnosed with APLA have a higher risk of recurrent thrombosis than do patients without known antibodies. Currently, warfarin is considered the anticoagulant of choice for prophylactic antithrombotic treatment for APLA patients after their first episode of thrombosis. In some patients with APLA who are treated with warfarin, the INR values determined on plasma are unreliable due to an influence of the APLA on the INR. In these individuals, alternative monitoring methods, such as factor II activity, chromogenic factor X activity or prothrombin-proconvertin time should be used to assess adequate anticoagulation. These tests are expensive and not widely available to some clinicians. Point-of-care (POC) instruments, on the other hand, are readily accessible to clinicians. Previous research has shown that INR values from 3 older point-of-care (POC) instruments are unreliable in 1/3 of APLA patients (CoaguChekTM, ProTimeTM, INRatioTM). However, there are now newer versions of these POC instruments available (CoaguChek XSTM, an investigational ProTime device, and a newer INRatioTM device) and it is unknown if these newer POC instruments are reliable in patients with APLA. The purpose of this study is to determine whether newer POC instruments are reliable in patients with APLA.

Conditions

• Antiphospholipid Syndrome

Interventions

Type	Name	Description
DEVICE	INR by point-of-care instruments and venopuncture	Three fingersticks will be performed and from each one drop of capillary or venous whole blood collected from a fingerstick performed by the primary investigator to measure PT/INR using the CoaguChekXSTM (10 microliters), ProTimeTM (27 microliters), the investigational ProTime, and INRatioTM 15 microliters) point-of-care instruments and one i.v. blood draw (20 mL of blood) will be performed by a phlebotomist.

Timeline

• Start date: 2009-03-01
• Primary completion: 2009-05-01
• Completion: 2009-05-01
• First posted: 2009-04-08
• Last updated: 2012-10-15

Locations

1 site across 1 country: United States