The demand for blood in the U.S. remains about the same. However, the supply is way down. All the blood collections in the hurricane area have stopped. Other parts of the country have to make up the shortage caused by all the usual donors in the gulf area not being able to provide blood.
I know for a fact that the shortage is so great that blood in Arizona is being picked up for immediate processing in the middle of the day at some of the drives, instead of waiting until the end of the day to process all of the blood from the drive at the same time.
It takes about 36 hours after the blood reaches the lab for processing before the blood is ready to be shipped to hospitals. The shortage seems to be so great that it is necessary to get blood to the lab as soon as possible.
In addition to the gulf area, a large number of donors in Southern California are not able to donate at this time due to possible exposure to West Nile Virus. Under the best of conditions, local blood needs are met by local donors. At this time, a lot of blood is being shipped around the country to meet immediate needs.
If you need blood today, you better hope enough blood was collected two days or three days ago. If not, it won't be there for you.