• Current laboratory testing methods (e.g., ELISA, FRET) require specialty lab with turnaround times up to 3 days3,4 HemosIL AcuStar ADAMTS13 Activity assay helps improve quality of patient care and efficiency when TTP is suspected Scenario 1: Send out ADAMTS13 activity test while initiating PLEX Day 1 Day 2 Day 3 Day 4 Continue PLEX until Aims: To evaluate the performance of a rapid, fully-automated ADAMTS13 activity assay. From Donna Lawler, University of Wisconsin, Hi George. The format is GTR00000001.1, with a leading prefix 'GTR' followed by 8 digits, a period, then 1 or more digits representing the version. Testing Algorithm. Consideration should also be given to testing a pre-plasma exchange sample for ADAMTS13 activity assay using a different test method, as results between methods may be discrepant. We are investigating the possibility of bringing an assay for ADAMTS 13 activity in house. The strengths of this test include: CAP accredited laboratory; CLIA-certified personnel performing clinical testing in a CLIA-certified laboratory; Powerful sequencing technologies, advanced target enrichment methods and precision bioinformatics pipelines ensure superior analytical performance Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy caused by severely reduced activity of the von-Willebrand factor-cleaving protease ADAMTS13, mainly caused by anti-ADAMTS-13 antibodies. If specific inhibition is apparent, the titer of the inhibitor will be determined. ADAMTS13 testing is crucial for an early diagnosis and optimal management of acute TTP. We are looking at the two methods available (ELISA and FRET) and I am wondering what your experience is with either of these assays. After testing, the residual activity is calculated, and the inhibitor concentration is expressed in … We performed a method … Hi, Donna, thanks for your question. The inhibitor screen and titer assay are performed by using mixing studies that are similar to the Bethesda assay. The patient’s sample is heat-inactivated and mixed with an equal volume of pooled normal plasma (PNP) before testing. Although several test systems for ADAMTS13 measurement exist, long turn-around times hamper the usability in daily practice. GTR Test ID Help Each Test is a specific, orderable test from a particular laboratory, and is assigned a unique GTR accession number. ADAMTS13 Sequence Analysis. The use of the ADAMTS13 activity assay as an in-house screening test for A-TTP contributed to more efficient use of TPE in addition to promoting more appropriate treatment for patients. When the diagnosis of TTP is established, the patient should be evaluated for antibodies against ADAMTS13. If the ADAMTS13 activity assay is less than 30%, an inhibitor screen will be performed to look for specific ADAMTS13 inhibition. Testing begins with ADAMTS13 activity assay to evaluate the percent activity. A method ADAMTS13 activity is measured by a Fluorescence Resonance Transfer (FRET) Assay in which fluorescence is detected when a synthetic von Willebrand Factor peptide (VWF73) is cleaved by ADAMTS13. We evaluated the performance of the HemosIL AcuStar ADAMTS13 activity assay (Instrumentation Laboratory, Bedford, Massachusetts, United States), a fully automat-ed chemiluminescent immunoassay with an analytical time of 33minutes. ADM13 : The ADAMTS13 activity is measured by a fluorescence resonance energy transfer (FRET)-based assay using a 73 amino-acid peptide (FRETS-VWF73) of von Willebrand factor (VWF) as substrate. Rapid ADAMTS13 testing is crucial for early diagnosis and optimal management of TTP patients. I would love to hear from anyone that does the ELISA method. ADAMTS13 inhibitors are measured using the same ELISA method. For strengths, this is the first published multicenter study on the use of the new, fast, precise test for ADAMTS13 activity.