Background: ADAMTS13 activity is a unique marker for thrombotic thrombocytopenic purpura (TTP) which helps differentiate TTP patients from those suffering other more common thrombotic microangiopathies (TMA) and also less frequent conditions such as hemolytic uremic syndrome. In routine, a fully automated assay, delivering ADAMTS13 activity results within less than 30 minutes and without need to batch samples, spares the cost of unnecessary treatments and improves the overall outcome of the patient care.

Aims: The aim of this study was to evaluate the performance of the new fully  automated ADAMTS13 activity assay in routine use by correlating the reults with those of the ADAMTS13 activity ELISA.

Methods: The Technofluor ADAMTS13 activity assay is based on a modified FRETS-VWF73-Fluorescence-Quenching-Substrate and can be performed fully automated on the coagulation analyzer Ceveron s100. A calibration curve is performed once per substrate lot. A method comparison study with 202 routine TMA patient samples was performed, comparing this new assay with ADAMTS13 activity ELISA. Both assays are calibrated against the WHO 1 st International Standard ADAMTS13 Plasma.

Results: Technofluor ADAMTS13 activity assay showed good correlation with ELISA (r 0.9246) assay, with the Passing-Bablok equation – Ceveron (IU/mL) = 0.00575 + 1.113 ELISA (IU/mL). The study revealed high agreement with ELISA (Kappa 0.924) in classifying TTP patients with a deficiency of ADAMTS13 activity <0.01IU/mL.

Conclusions: The fully automated ADAMTS13 activity assay showed a good correlation with the ELISA and excellent clinical performance for the diagnosis of severe ADAMTS13 deficiency. This fully automated ADAMTS13 activity assay is the optimal option for rapid evaluation of ADAMTS13 activity to confirm the diagnosis of acute clinical TTP in emergency settings.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/evaluation-of-a-new-fully-automated-adamts13-activity-assay/