It is screened for nasty blood-bourne infections (such as HIV and hepatitis), and usually separated into red blood, platelets and plasma. All of these are used differently. For example, plasma is often used when a lot of blood has been lost, but can also be used to make vaccinations and eye drops (I had a job turning a bag of blood into eye drops many years ago: easy to do and the patient received their own plasma to put in their eyes to help with healing - kinda like squirting breast milk into the eyes, in a way).

It can go straight to a recepient, but that's really quite rare.