Our November, 2020 Quick Question attracted 37 participants. Here is the stem: “Which VWF activity assay is preferred at your facility [check 10-31-20 post]?” The selections were…
- VWF:RCo: 58% 
- VWF:GP1bR: 3% 
- VWF:GP1gM: 14% 
- VWF:Ab: 3% 
- VWF:CBA: 22% *
The time-honored Ristocetin cofactor assay remains the most prevalent of VWF activity assays. The reference provided in the 10-31-20 post names VWF:GP1bR as Ristocetin-induced binding of VWF to recombinanit GP ib fragment, and VWF:GP1gM as spontaneous VWF binding to gain of function mutant GP Ib fragment. These are the newest of VWF activity assays that offer improved precision compared to VWF:RCo.
*The VWF:CBA tally is approximate, as the poll was corrupted by spam.