ADAMTS13 and preeclampsia: Furthermore, it was interesting to find that ADAMTS13 activity was significantly lower in patients with preeclampsia [median (IQR, p25–p75): 70.1% (16.9, 65.3–82.2) vs. 89.5% (25.2, 71.8–97), p = 0.012], but remained within normal limits in both groups.