Objective: To determine if monitoring antiphospholipid syndrome (APS) patients on warfarin by factor II activity assay (FIIAA) would decrease
thrombus risk or if elevating international normalized ratio (INR) goal based on FIIAA would increase bleeding risk.
Methods: A community hospital retrospective chart review was conducted on anticoagulation clinic APS patients (n=49) over 50 months. Patients
with an APS-associated diagnosis compliant warfarin therapy were included as long as they were at least 18 years of age. Patients were excluded
if they were monitored in the clinic for <6 months, became pregnant, or developed cancer during the study period. The primary outcome was to
determine if FIIAA monitoring reduced thrombus risk or increased bleeding risk.
Results: No statistical difference in bleeding event, age, comorbidities, or sex was determined between the FIIAA monitored and non-FIIAA monitored
group. Thromboembolic events approached statistical significance (p=0.053) in the monitored group. Two of the 3 patients had a subtherapeutic INR
and one had additional thrombophilias.
Conclusion: Thromboembolic risk was not reduced by FIIAA monitoring in APS patients. INR goal increases based on FIIAA monitoring did not
increase bleeding risk. A larger study may help determine the most appropriate way to monitor APS patients using warfarin.
Keywords: Antiphospholipid syndrome, Factor II activity assay, Warfarin, Thrombosis, Anticoagulation and bleeding.


Author Biographies

AMY CHRISTOPHER, St. Elizabeth Healthcare

Pharmacy Department

Anticoagulation Clinic and Oncology Infusion

PharmD, BCPS

Michelle Sweet, St. Elizabeth Healthcare

Pharmacy Department



1. Lim W. Antiphospholipid syndrome. Hematology Am Soc Hematol Educ Program 2013;2013(1):675-80.
2. Baker WF Jr, Bick RL. The clinical spectrum of antiphospholipid syndrome. Hematol Oncol Clin North Am 2008;22(1):33-52.
3. Coaguchek® XS PT Test [Package Insert] Roche Diagnostics USA, Indianapolis, IN, USA; 2009.
4. Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ, et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141 2 Suppl:e152S-84.
5. Baumann Kreuziger LM, Datta YH, Johnson AD, Zantek ND, Shanley R, Reding MT. Monitoring anticoagulation in patients with an unreliable prothrombin time/international normalized ratio: Factor II versus chromogenic factor X testing. Blood Coagul Fibrinolysis 2014;25(3):232-6.
6. Farmer-Boatwright MK, Roubey RA. Venous thrombosis in the antiphospholipid syndrome. Arterioscler Thromb Vasc Biol 2009;29(3):321-5.
7. Moll S, Ortel TL. Monitoring warfarin therapy in patients with lupus anticoagulants. Ann Intern Med 1997;127(3):177-85.
8. Rosborough TK, Shepherd MF. Unreliability of international normalized ratio for monitoring warfarin therapy in patients with lupus anticoagulant. Pharmacotherapy 2004;24(7):838-42.
9. Anila KN, Emmanuel J. Clinical pharmacist governed anticoagulation service in stroke unit of a tertiary care teaching hospital. Asian J Pharm Clin Res 2013;6(2):149-52.
10. Al-Meman A. I-Stat, Coaguchek XS Plus, and hemochron versus reference laboratory INRS: Pharmacist-managed clinics. Int J Pharm Pharm Sci 2015;7(1):284-8.
11. Schulman S, Kearon C; Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. Definition of major bleeding in clinical investigations of antihemostatic medicinal products in non-surgical patients. J Thromb Haemost 2005;3(4):692-4.
12. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol 1992;45(6):613-9.
246 Views | 345 Downloads
How to Cite
CHRISTOPHER, A., and M. Sweet. “ASSESSING ANTICOAGULATION SAFETY AND EFFICACY IN ANTIPHOSPHOLIPID SYNDROME PATIENTS MONITORED BY FACTOR II ACTIVITY ASSAY”. Asian Journal of Pharmaceutical and Clinical Research, Vol. 10, no. 3, Mar. 2017, pp. 398-01, doi:10.22159/ajpcr.2017.v10i3.16355.
Original Article(s)