1. Coagulation Reference Laboratory, Department of Clinical Chemistry and Laboratory Medicine , Leiden University Medical Center , P.O. Box 9600 , 2300 RC Leiden , The Netherlands
2. Department of Thrombosis and Hemostasis , Leiden University Medical Center , Leiden , The Netherlands , Phone: +31 71 526 1942
3. Coagulation Reference Laboratory, Department of Clinical Chemistry and Laboratory Medicine , Leiden University Medical Center , Leiden , The Netherlands