Recommendations for clinical laboratory testing for antithrombin deficiency; Communication from the SSC of the ISTH

Authors

Elizabeth M. Van Cott, Coagulation Laboratory, Massachusetts General Hospital, Boston, MA, USA
Christelle Orlando, Department of Haematology, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
Gary W. Moore, Diagnostic Haemostasis and Thrombosis, Viapath Analytics, Guy's & St. Thomas' Hospitals, London, UK
Peter C. Cooper, Coagulation Department, Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, Sheffield, UK
Piet Meijer, ECAT Foundation, Voorschoten, Netherlands
Richard Marlar, Department of Pathology, Special Coagulation Laboratory, TriCore Reference Laboratories, University of New Mexico, Albuquerque, NM, USA
Subcommittee on Plasma Coagulation Inhibitors

Document Type

Article

Publication Date

1-1-2020

Abstract

Hereditary deficiency of antithrombin, a natural anticoagulant, causes a thrombophilia with a high risk for venous thromboembolism. Guidance for laboratory testing to diagnose antithrombin deficiency include the use of an activity assay for initial testing, performing an antigen test and activity-to-antigen ratio when the activity level is low, using pediatric reference ranges until the age of 6 months, excluding acquired causes of low antithrombin (e.g. liver dysfunction, proteinuria, heparin, disseminated intravascular coagulation, thrombosis, surgery) or falsely normal/elevated results (e.g. argatroban, bivalirudin, dabigatran in factor IIa-based assays; rivaroxaban, apixaban, edoxaban, but not betrixaban in Xa-based assays). Molecular testing, if available, may help determine the risk for thrombosis as this might vary among the different mutations. Moreover, it will identify mutations that can be missed by traditional activity assays. Strategies for interpreting laboratory test results are provided.

Recommended Citation

Van Cott EM, Orlando C, Moore GW, Cooper PC, Meijer P, Marlar R; Subcommittee on Plasma Coagulation Inhibitors. Recommendations for clinical laboratory testing for antithrombin deficiency; Communication from the SSC of the ISTH. J Thromb Haemost. 2020 Jan;18(1):17-22. doi: 10.1111/jth.14648. PMID: 31894660.