the fundamental reason for it

Arriving late for a delivery, I passed the patients sat in the waiting room, turning up for their appointments early whilst I swanned in fifteen minutes later than agreed with the hospital unit.
After dropping off the days doses, I waited for the blood to be ready to collect and bring back for labelling, and saw the hospital specialist struggling to withdraw it from an frail elderly lady into a large looking 60ml syringe.

Always important to remember who the job is for.