Laboratory Testing for the Lupus Anticoagulant; Approved Guideline
|Publication Date:||1 April 2014|
This document provides guidance for the performance and interpretation of screening assays, confirmatory assays, and mixing tests used to identify the lupus anticoagulant (LA). It is intended to assist in standardization of LA testing and it addresses preexamination issues, examination concerns, and postexamination matters that pertain to interpretation of individual tests or combinations of assays. Recommendations from this guideline, when feasible, harmonize with other national and international guidelines currently in existence. Taken together, standardization and harmonization will permit laboratories to improve the quality and interpretation of their LA testing.
The intended users of this guideline are laboratory personnel responsible for performing LA testing, physicians (eg, hematologists, pathologists, rheumatologists), external quality assessment (EQA) programs, researchers, and manufacturers of reagents used in LA testing.
Two types of methodologies are used for the diagnosis of the antiphospholipid syndrome (APS). This guideline is limited to clot-based coagulation assays used as surrogates for identifying LA-a strong risk factor for thrombosis. The guideline will not address solid-phase testing for anti-phospholipid (aPL) (eg, anti-cardiolipin [aCL] or anti-β2 glycoprotein I [aβ2GPI]), because detection of these specific antibodies may or may not relate to the laboratory anomaly of a prolonged activated partial thromboplastin time (APTT).