Try to draw DFD for this system
The Blood Bank Testing Unit. This is one unit within the College Street Red Cross Blood Donor Centre.
On the day following a blood donation, the Blood Bank unit tests all blood for blood type and potential
viral agents. They send the results of these tests to the Processing Office (another unit of the Centre). For
each tested blood unit, they fill out a form which lists the blood unit number, the blood type, the date and
the results of the test. If the tests indicate that the blood may be contaminated with a viral agent, the blood
unit is destroyed. This is indicated on the test form.
Blood units have a limited shelf life. The Blood Bank receives a list every day of those units which have
exceeded their shelf life. These are discarded and the list sent back to the Processing Office with a signed
indication of the disposal of the units.
The Blood Bank also distributes blood to various hospitals requesting blood. Requests usually come in for
specific blood types. The Blood Bank prepares refrigerated containers of these units and distributes them
to the hospital vans when they arrive to pick up their supply. The Blood Bank receives a listing for each
hospital and the specific units of blood to supply to the hospital from the Processing Office. The order is
printed in triplicate. When the order is filled, the lab technician signs the order and returns a copy to the
Processing Office. A copy of it travels with the blood to the requesting hospital. The final copy is kept in
the Blood Bank records but discarded after one year.