title: Laboratory identification of lupus anticoagulants using the combination of activated partial thromboplastin time and Russell's viper venom at two phospholipid concentrations.
abstract: The most appropriate combination of tests for lupus anticoagulants (LA) is unknown. The standard double centrifugation method to prepare plasma was inadequate for platelet elimination, interfering with kaolin clotting time and mixing studies. In the present study, the percentage correction of activated partial thromboplastin time (APTT) and Russell's viper venom time (RVVT) by high compared with low concentrations of phospholipid was used for both screening and confirmation of LA. Abnormality in either one was reported as positive. The specificity of the tests in 122 individuals without LA was 100 per cent for RVVT and 96.7 per cent for APTT, which yielded false positive by heparin. The mixing study was omitted from the authors' strategy without decreasing the specificity. In 795 patients with thrombosis, LA was detectable in 6.03 per cent. The sensitivity of diluted activated partial thromboplastin time (dAPTT) and diluted Russell's viper venom time (dRVVT) alone, compared with the combination of the two was 83.3 per cent and 79.2 per cent respectively. Therefore, this new test scheme is a simple, inexpensive and efficient method for Thai patients.
authors.affiliation: Division of Hematology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Benjaporn
authors.initials: B
authors.lastname: Akkawat
authors.forename: Veena
authors.initials: V
authors.lastname: Chantarangkul
authors.forename: Ponlapat
authors.initials: P
authors.lastname: Rojnuckarin
authors.forename: Jumlong
authors.initials: J
authors.lastname: Juntiang
mesh_terms: D016736:Antiphospholipid Syndrome / Q000097:blood* / Q000175:diagnosis*; D019411:Clinical Laboratory Techniques; D004305:Dose-Response Relationship, Drug; D006801:Humans; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D010314:Partial Thromboplastin Time; D010743:Phospholipids / Q000008:administration & dosage*; D011517:Prothrombin Time; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D016682:Lupus Coagulation Inhibitor; D010743:Phospholipids