O-negative blood, the most universal and therefore in greatest demand is running low at local United Blood Services outlets.

Lesli Asay, regional donor recruitment director says in emergencies, when there's no time to cross match blood, O-negative is what's used.

"In addition to that, O-negative blood is what's used for infants, because they don't carry the antigens and antibodies on their cells that could cause a problem in a new borne infant."

Asay says currently United Blood Services is helping transfuse four infants regionally. So the need is acute and they're asking for those able to donate to roll up their sleeves.

She says donating takes about an hour, faster for those who've already been through a medical history.

United Blood Services is open every day except Sunday at 1416 East A Street in Casper.

Monday and Friday 6 a.m. to 2 p.m., Wednesdays 10 a.m. to 6 p.m. and the 2nd and 4th Sunday of each month from 9AM - 3PM.

Donors may call (307) 237-2328 or 1-800-365-4450, or visit www.bloodhero.com to make a convenient appointment to donate.

Volunteer donors must be at least 16, have a signed minor donor permit, weigh at least 110 pounds and be in good health. Donors between the ages of 16 and 22 have additional requirements.