Can a serum be separated from plasma?

Whole blood is collected by blood banks and plasma is separated there. The same plasma is then processed to separate albumin, immunoglobulins, and factors through the fractionation process.

Can we get serum (which is theoretically plasma-clotting factors) from the remnant of the fractionation for further use?

Will it have a similar characteristics as the serum directly separated from whole blood?

Is ABO status matters in such serum?