Moore Gary W, Kumano Osamu
Department of Haemostasis and Thrombosis, Viapath Analytics, Guy's & St. Thomas' Hospitals, London, UK.
Protein Technology, Sysmex Corporation, Kobe, Japan.
J Thromb Haemost. 2020 Feb;18(2):439-444. doi: 10.1111/jth.14669. Epub 2019 Nov 15.
Multicenter studies reveal that diagnostic efficacy of lupus anticoagulant (LA) assays is enhanced if cut-offs are locally generated. However, a potential confounder is the inevitable use of separate normal donor populations.
Generate cut-offs for multiple LA reagents with the same analyzer and normal donor plasmas.
Cut-offs for screen ratio, confirm ratio, percent correction of screen ratio by confirm ratio, and normalized screen/confirm ratio (NSCR) were derived from the same 50 normal donor plasmas for screen and confirm pairs for two dilute Russell's viper venom time reagents, LA1/LA2 and HEMOCLOT™ LA-S/LA-C, and two APTTs, Actin FSL/FS and Cephen LS/Cephen. The cut-offs were challenged with plasmas from 20 triple-positive APS patients and 25 plasmas from LA-negative, thrombotic patients.
Cut-offs for screen ratio, confirm ratio, percent correction, and NSCR, respectively, were 1.12/1.08/8.3/1.09 for LA1/LA2; 1.17/1.10/13.6/1.13 for HEMOCLOT™ LA-S/LA-C; 1.12/1.13/9.7/1.10 for Actin FSL/FS; 1.09/1.13/11.0/1.11 for Cephen LS/Cephen. LA1 and LA-S screens were elevated in 19/20 and 16/20 triple-positive plasmas, respectively, while 20/20 were detected with both via integrated interpretation ie, percent correction or NSCR irrespective of screen elevation. Actin FSL and Cephen LS screens were elevated in 17/20 and 19/20 triple-positive plasmas, respectively, while one more LA was detected with Actin FSL via integrated interpretation, but not for Cephen LS. Integrated interpretation suggested 5/25 LA-negative plasmas contained weak LA (two with Actin FSL/FS, two with LA1/LA2, one with LA-S/LA-R).
Employing the same normal donor plasmas and analytical platform does not compensate for between-reagent differences when generating LA assay cut-offs.
多中心研究表明，如果采用本地生成的临界值，狼疮抗凝物（LA）检测的诊断效能会得到提高。然而，一个潜在的混杂因素是不可避免地使用不同的正常供体群体。
使用同一分析仪和正常供体血浆为多种LA试剂生成临界值。
筛选率、确证率、确证率对筛选率的校正百分比以及标准化筛选/确证率（NSCR）的临界值，是从相同的50份正常供体血浆中得出的，这些血浆用于两种稀释的罗素蝰蛇毒时间试剂（LA1/LA2和HEMOCLOT™ LA-S/LA-C）以及两种活化部分凝血活酶时间试剂（Actin FSL/FS和Cephen LS/Cephen）的筛选和确证检测。用来自20例三阳性抗磷脂综合征（APS）患者的血浆和25例LA阴性的血栓形成患者的血浆对这些临界值进行验证。
LA1/LA2的筛选率、确证率、校正百分比和NSCR的临界值分别为1.12/1.08/8.3/1.09；HEMOCLOT™ LA-S/LA-C为1.17/1.10/13.6/1.13；Actin FSL/FS为1.12/1.13/9.7/1.10；Cephen LS/Cephen为1.09/1.13/11.0/1.11。在20例三阳性血浆中，LA1和LA-S的筛选检测结果分别有19/20和16/20升高，而通过综合解读（即校正百分比或NSCR），无论筛选结果是否升高，两种试剂均能检测出所有20例。Actin FSL和Cephen LS的筛选检测结果在20例三阳性血浆中分别有17/20和19/20升高，通过综合解读，Actin FSL能多检测出1例LA，但Cephen LS不能。综合解读表明，25例LA阴性血浆中有5例含有弱LA（2例与Actin FSL/FS有关，2例与LA1/LA2有关，1例与LA-S/LA-R有关）。
在生成LA检测临界值时，使用相同的正常供体血浆和分析平台并不能弥补试剂之间的差异。
