Donor shortage threatens rare-blood carriers

According to the union's rules, six months must elapse between each donation, while people recovering from a cold or who have taken medicine have to wait a week after the all-clear before they are allowed to give blood. Women who are menstruating or breastfeeding are not allowed to donate. "Most of us don't visit centers to donate blood regularly. Our resource is fairly precious, so we must make every drop count," Xie said.

According to Wang, the largest amount donated by a single volunteer was 20,000 cubic centimeters, roughly five times the volume of blood in the average adult body, which required at least 50 separate donations.

"Some volunteers have stopped smoking or drinking alcohol and going to bed late to ensure they are healthy enough to make an urgent blood donation. Some slender women have even attempted to gain weight to meet the requirement that donors must weigh at least 45 kilograms," he said.

The regional heads usually look for candidates within their home province or municipality, but sometimes volunteers rush to distant locations to donate blood.

In February, the union's branch in Anhui province was looking for donors with B negative blood for a 60-something woman who was awaiting surgery. No one could be found within the immediate locality, but Kang Huiming, a primary school teacher in Lianshui county, Jiangsu province, volunteered to help. That night she asked a friend to drive her to the hospital, six hours from her home.

"It's not about showing your benevolence - it's about saving a life," Kang said.

Although the number of members has grown gradually, some quit the union after a couple of years.

"When they first join, some people feel like they are superman and can help anybody. But if their help fails to save a life, it's hard to drag them out of the low mood," Wang said.

Xie, in Shanghai, recalled an unsuccessful attempt to save the life of a 7-year-old girl with leukemia. Having received a phone call from the girl's mother, he immediately started looking for donors. Eventually, he contacted a suitable volunteer, but the man was on a business trip to Henan province in Central China. Desperate to help, the volunteer concluded his trip, flew back to Shanghai and rushed to the hospital. Unfortunately, the girl died just as he arrived.

"Many of the volunteers were sleepless that night. The volunteer who flew back even blamed himself for taking the trip," Xie said.

Others have been lured away by money. Trading in blood is illegal under Chinese law, but "black" collection and supply agencies still exist. According to Xie, 400 cc of rhesus negative blood can fetch more than 20,000 yuan ($2,900) on the black market.