Plasma donors enrolled in the IMPACT trial (n= 3,443).
Personalised nomogram incorporating height, weight, and haematocrit (experimental, n= 1,717).
Established weight-based nomogram (control, n= 1,726).
The predicted mean number of repeat donations was similar between the control and experimental arms (6.82 vs. 6.62). Overall, the predicted mean number of repeat donations was significantly higher in males compared with females. Naïve donors had on average 2.8/2.7 (control/experimental) fewer repeat donations compared with experienced donors. In 23,137 donations from 3,443 donors, 798 donors (376 control, 422 experimental) had at least one deferral. The predicted mean number of deferrals in all categories of interest was not statistically different between the study arms.