United Blood Services says blood supplies are critically low.
"There is an urgent need for O positive and especially O negative," said Nyla Emerson, spokewoman. "If more donations than normal are not collected in the next few days, an emergency will exist."
Blood type O is the most common type. People who have donated in the past are asked to give now if it has been at least eight weeks since their last donation.
All blood types are needed and new donors are encouraged to begin.
To make an appointment call United Blood Services at 324-6454 or 887-9111. It is at 1125 Terminal Way in Reno and 256 E. Winnie Lane in Carson City.