Beijing's health authority has issued a plea to citizens with the rhesus (Rh) negative blood type to make donations to build up supplies for overseas athletes at next year's Olympics.

The health authorities face a shortage of the blood type as only three in 10,000 Han Chinese are Rh negative, according to official figures.

"Beijing will welcome more than 500,000 foreign guests during the Games and we need to reinforce our blood banks," Deng Xiaohong, deputy director of the Beijing municipal health administration, said.

A pressing job between now and the Games' opening ceremony in August is to expand storage of the Rh-negative blood, which is found in 15 percent of Westerners, she said.

Beijing-based hospitals need a total of 200,000 cc of Rh-negative blood a year for clinical use, Deng said.

"When the blood is out of supply, we also ask other provinces for help," she said.

New technologies have prolonged the shelf life of the Rh-negative blood to 10 years by storing it at minus 85 C.

Occasional reports of blood shortages have prompted several Chinese cities to set up special databanks with details of the Rh-negative donors, including their overall health situation, donation history and past illnesses, to ensure an adequate supply in case of emergencies.

It can be fatal if a Rh-negative patient receives transfusions of a different blood type. Expectant mothers with Rh-negative blood are also vulnerable to miscarriages when the fetuses have a different blood type.

(Xinhua News Agency September 7, 2007)