A 21-year-old German girl recently donated her "panda blood", or Rh-negative blood, on two occasions to save a 75-year-old woman in Wenzhou, Zhejiang province.

Christa Maria Idel, a language student at Zhejiang University, came to China to study for one semester, adopting the Chinese name Gao Xiongmao.

When she found out that her blood type is Rh-negative, she called herself Xiongmao, the Chinese name for panda.

She is 1.75 meters tall, so she surnamed herself Gao, which means tall in Chinese.

"I was told that only 0.3 percent of the population in China have 'panda blood'. The proportion in some Western countries is as high as 6 percent or higher. This was news to me," she said.

Out of curiosity, Gao searched on Weibo to find out more information about the blood type.

She found a post asking for help from the family of an old woman who suffers from aplastic anemia and fainted in October.

She left a message on the post and a doctor contacted her a couple of days later.

The old woman, Kong Qinmei, has merely one-fiftieth of the normal platelet level and requires blood transfusions to keep her alive.