Each donation of whole blood or its component intended for transfusion
constitutes a single batch. The sterility of the blood should be checked
on 1% of the blood units collected or 4 per month whichever is higher.
The sterility test should not be done by a method that entails breaching
the final container before the blood is transfused. The blood sample
from the tubing attached to the container should be used for sterility
testing i.e. culture at 4oC, 22oC & 37oC.