title: Sensitivity of the activated partial thromboplastin time, the dilute Russell's viper venom time, and the kaolin clotting time for the detection of the lupus anticoagulant: a direct comparison using plasma dilutions.
abstract: Increasing dilutions of lupus anticoagulant (LA) plasmas from twelve patients were used to directly compare the sensitivity of four tests for LA. The tests evaluated were the modified Bell and Alton activated partial thromboplastin time (APTT), an APTT using a commercially prepared partial thromboplastin (Platelin LS APTT), a modified dilute Russell's viper venom time (DRVVT), and a modified kaolin clotting time (KCT). LAs were detected in all twelve plasmas by each of three tests and eleven of twelve plasmas in a fourth test when undiluted patient plasma was used. Repeating the tests after diluting the LA plasmas with normal platelet-free plasma (PFP) showed that the KCT was the most sensitive test for LA, detecting eleven of twelve LAs at a dilution of 10% patient plasma and ten of twelve LAs at a dilution of 5% patient plasma. The modified Bell and Alton APTT and the modified DRVVT had similar sensitivities at a patient plasma concentration of 10%, detecting seven of twelve and eight of twelve LAs, respectively. The Platelin LS APTT detected only four of twelve LAs at a patient plasma concentration of 10%. Our results indicate that the modified KCT is a sensitive method for the detection of LAs. The modified Bell and Alton APTT and the DRVVT were less sensitive.
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Martin
authors.forename: D W
authors.initials: DW
authors.lastname: Branch
authors.forename: G M
authors.initials: GM
authors.lastname: Rodgers
mesh_terms: D006801:Humans; D007201:Indicator Dilution Techniques; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D010314:Partial Thromboplastin Time; D010743:Phospholipids / Q000097:blood*; D011517:Prothrombin Time; D012680:Sensitivity and Specificity
chemical_list: D016682:Lupus Coagulation Inhibitor; D010743:Phospholipids