Welcome to the site, you will love it here. In my MANY years in the field the decision as to how many staff members you have working in the Blood Bank. Lots of things play into this decision. Do you have automation, since you are a trauma center you are no doubt busy on all shifts. As a manager I was always looking at the famous "productivity standard", a number some bean counter pulled out of "thin air" Skill level, level of BB expertise, years of experience all play into staffing. So as you can see there really isn't one answer. Deny's suggestion is good but you should pull in your director before making any decisions and settling on an number that may not be adequate bench coverage and overstaffing is not good either. Good luck, check back often there is lots of good info on this site.