The Lancet Haematology
Volume 4, No. 4, e157–e164, April 2017
Dr Pavan K Bendapudi, MD, Shelley Hurwitz, PhD, Ashley Fry, MD, Marisa B Marques, MD, Stephen W Waldo, MD, Ang Li, MD, Lova Sun, MD, Vivek Upadhyay, MD, Ayad Hamdan, MD, Andrew M Brunner, MD, John M Gansner, MD, Srinivas Viswanathan, MD, Richard M Kaufman, MD, Lynne Uhl, MD, Christopher P Stowell, MD, Walter H Dzik, MD, Robert S Makar, MD
Among the syndromes characterised by thrombotic microangiopathy, thrombotic thrombocytopenic purpura is distinguished by a severe deficiency in the ADAMTS13 enzyme. Patients with this disorder need urgent treatment with plasma exchange. Because ADAMTS13 activity testing typically requires prolonged turnaround times and might be unavailable in resource-poor settings, a method to rapidly assess the likelihood of severe ADAMTS13 deficiency is needed.
All consecutive adult patients presenting to three large academic medical centres in Boston, MA, USA, with thrombotic microangiopathy and a possible diagnosis of thrombotic thrombocytopenic purpura between Jan 8, 2004, and Dec 6, 2015, were included in an ongoing multi-institutional registry (the Harvard TMA Research Collaborative). Univariate analysis was used to identify covariates for a logistic regression model predictive of severe ADAMTS13 deficiency (≤10% activity). A clinical point score was generated, and its diagnostic performance was assessed using internal and external validation cohorts and compared to clinical assessment alone.