Identification of ADAMTS13 inhibitors in acquired TTP

Emmanuel J. Favaloro, Kent Chapman, Soma Mohammed, Ronny Vong, Leonardo Pasalic

Research output: Book chapter/Published conference paperChapter (peer-reviewed)peer-review

5 Citations (Scopus)


Thrombotic thrombocytopenic purpura (TTP) is a prothrombotic condition caused by a deficiency of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). In turn, ADAMTS13 (also called von Willebrand factor (VWF) cleaving protease (VWFCP)) acts to cleave VWF multimers and thus reduce plasma VWF activity. In the absence of ADAMTS13 (i.e., in TTP), plasma VWF accumulates, in particular as "ultra-large" VWF multimers, and this leads to thrombosis. In most patients with confirmed TTP, ADAMTS13 deficiency is an acquired disorder due to the development of antibodies against ADAMTS13, which either promote clearance of ADAMTS13 from circulation or cause inhibition of ADAMTS13 activity. The current report describes a protocol for assessment of ADAMTS13 inhibitors, being antibodies that inhibit ADAMTS13 activity. The protocol reflects the technical steps that help identify inhibitors to ADAMTS13, whereby mixtures of patient plasma and normal plasma are then tested for residual ADAMTS13 activity in a Bethesda-like assay. The residual ADAMTS13 activity can be assessed by a variety of assays, with a rapid test able to be performed within 35 minutes on the AcuStar instrument (Werfen/Instrumentation Laboratory) used as an example in this protocol.
Original languageEnglish
Title of host publicationHemostasis and thrombosis
Subtitle of host publicationMethods and protocols
EditorsEmmanuel J. Favaloro , Robert C. Gosselin
Place of PublicationNew York
PublisherHumana Press
Number of pages17
ISBN (Electronic)9781071631751, 9781493971961
ISBN (Print)9781493971947
Publication statusPublished - 2023

Publication series

NameMethods in Molecular Biology
ISSN (Print)1064-3745
ISSN (Electronic)1940-6029


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