title: An improved test to identify aPC-resistant factor V-Leiden.
abstract: A functional clotting assay was recently reported to detect the factor V-Leiden mutation (R506Q) in patients receiving oral anticoagulants and in patients with Lupus Anticoagulant inhibitor. The original assay (Dahlback) to detect resistance to activated protein C (aPC-resistance) frequently gave unreliable findings in these patients. The change in the method is the use of bovine thromboplastin in a PT-derived assay, with a 1:10 sample dilution. In these conditions a reference normal plasma gives a prolongation of more than 35 seconds, while samples with a heterozygous or homozygous mutation give a prolongation respectively of 10-18 seconds or less 2 seconds. The test is easily automated and quickly performed on ACL/3000, and the reproducibility is good.
authors.affiliation: Immunohematology and Transfusion Service, Luigi Sacco Hospital, Milan, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Preda
authors.forename: N
authors.initials: N
authors.lastname: Erba
authors.forename: S
authors.initials: S
authors.lastname: Figini
authors.forename: G C
authors.initials: GC
authors.lastname: Carniti
authors.forename: E
authors.initials: E
authors.lastname: Rossi
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D001778:Blood Coagulation Disorders / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D001780:Blood Coagulation Tests / Q000379:methods* / Q000706:statistics & numerical data; D002417:Cattle; D004351:Drug Resistance; D005069:Evaluation Studies as Topic; D005165:Factor V / Q000032:analysis* / Q000187:drug effects* / Q000235:genetics; D005169:Factor VIII / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D066298:In Vitro Techniques; D016682:Lupus Coagulation Inhibitor / Q000187:drug effects; D017354:Point Mutation; D011486:Protein C / Q000494:pharmacology*; D011817:Rabbits; D015203:Reproducibility of Results; D013925:Thromboplastin
chemical_list: D000925:Anticoagulants; D016682:Lupus Coagulation Inhibitor; D011486:Protein C; C095381:factor V Leiden; D005165:Factor V; D005169:Factor VIII; D006493:Heparin; D013925:Thromboplastin