For the second time in as many months, United Blood Services announced an emergency appeal for type O-negative blood donors.The ongoing need for O-negative blood remains critical. As of Monday morning, there were outstanding orders for 112 units of O- Negative blood.

United Blood Services in Casper is open Monday and Wednesday 10 a.m. to 6 p.m., Tuesday, Saturday and the 2nd, 4th & 5th Sundays from 9 a.m. to 2 p.m., and Friday 6 a.m. to 2 p.m. Donors may call 237-2328 to make an appointment or you may visit to complete the self-interview, on the day of donation, and then bring your printout to the center or mobile locations. Walk-ins are always welcome – appointments are encouraged. The center address is 2801 East 2nd Street, just down the hill from the Eastside Albertson's.

Only 6 percent of the population has O-negative blood, yet at hospital trauma centers, sometimes as much as 15 percent of the blood transfused is O-negative. That’s because O-negative blood is the universal blood type.

Volunteer blood donors must be at least 16, weigh a minimum of 110 pounds and be in good health. Additional height/weight requirements apply to donors 22 and younger, and donors who are 16 must have signed permission from a parent or guardian. For more information, visit With each donation, donors receive a free total cholesterol test and earn points in United Blood Services’ Hero in Me rewards program.