From Donna Lawler, University of Wisconsin, Hi George. We are investigating the possibility of bringing an assay for ADAMTS 13 activity in house. We are looking at the two methods available (ELISA and FRET) and I am wondering what your experience is with either of these assays. I would love to hear from anyone that does the ELISA method.
Hi, Donna, thanks for your question. One of our local labs in Alabama is also bringing the ADAMTS13 (VWF-cleaving pretease) activity assay in house, and their director is also undecided, but is engaged in an evaluation process. I have no direct experience with the assay, so I will (a) ask for comments from our participants, and (b), stay in touch with our nearby colleagues to learn what they have decided. Please visit Fritsma Factor from time to time to see comments as they arrive.
FRETS-VWF73 assay is still
The FRETS-VWF73 assay is still considered the gold standard. The chromogenic assay Technozym ELISA (Chr-VWF73) underestimates ADAMTS13 activity when compared to FRETS-VWF73 and sometimes may give false negative results according to these references:
Mackie I, et al. Discrepancies between ADAMTS13 activity assays in patients with thrombotic microangiopathies. Thromb Haemost. 2013;109:488–96.
Joly B et al. Evaluation of a chromogenic commercial assay using VWF-73 peptide for ADAMTS13 activity measurement. Thromb Res. 2014;134:1074–80.
Recently (with Blood Center of Wisconsin collaboration) another more sensitive FRETS assay was proposed, but we don’t know if it is commercially available. It is an optimized fluorogenic ADAMTS13 assay with increased sensitivity for the investigation of patients with thrombotic thrombocytopenic purpura: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3807872/