Over the past 20 years, Zhang Bi has donated her blood more than 130 times to help people in need.

Zhang, 44, an employee of a property management company in Yichang, Hubei province, first donated blood in 1998 while studying at Wuhan University of Technology.

"It was in the summer when I was walking along the street with my classmates, and medical workers were promoting the idea of voluntary blood donations," she recalled.

To mark her upcoming graduation with a degree in international trade and commerce, she decided to donate 200 milliliters of blood.

"In fact, I was a little nervous at the beginning," she said. "But with the nurse explaining things and providing guidance, I gained basic knowledge and finished the blood donation successfully."

After her graduation, she returned to her hometown of Yichang and began to donate blood once or twice a year. In May 2001, an incident personally touched Zhang and deepened her understanding of voluntary blood donation.

Her older brother, a traffic policeman, was attacked and stabbed in a lung after confiscating an illegally operated motorcycle. He suffered massive blood loss as a result of the wound. "Because of his poor blood coagulation, he needed a massive transfusion during his medical treatment," Zhang said.

But there was a shortage of supplies in the blood bank, so all the police officers in the city's public security bureau volunteered to donate blood.

"Finally, with the help of those eligible volunteers, my brother was saved," she said. "Before that time I considered voluntary blood donation as quite a routine act, but in fact it plays an important role in saving a patient, especially in an emergency."

From then on, she began to donate blood every six months, the maximum allowed, according to the Blood Donation Law.

In 2006, Zhang's father had heart bypass surgery and received a massive blood transfusion.

Zhang had donated so much blood in the past she had earned enough "credits" for the cost of her father's blood transfusion to be reimbursed by the city's blood center. "It was another time I realized the significance of blood donation for the whole society as well as every single family," she said. "Therefore, I hope I can try my best to help people in need and also repay those who helped my family through my blood donations."

The same year, Zhang started donating blood platelets after learning that this approach is necessary to treat patients with blood diseases.

"When I learned about this relatively new way of donating blood, I decided to donate platelets, which are useful for treating a range of conditions, such as leukemia and excessive blood loss," she said. "One of its advantages is that a small amount can be used to treat several patients."

However, for donors, platelet donation is more complicated. It requires more physical examinations with stricter standards.

The whole process takes nearly two hours, and may cause donors some discomfort.

Platelets are drawn from a donor's blood and passed through a cell-separating machine. After collecting the platelets, the machine returns the remaining blood components back to the donor's body.

Zhang donates platelets once or twice a month. The minimum interval is once every 15 days.

Sometimes when the local blood bank is facing a shortage, she immediately heads to the center to make a donation. "Each time I donate one or two therapeutic doses of blood platelets, according to my health situation," she said.

Through years of making donation, Zhang has gained a lot of knowledge on blood and health. "To keep myself in the best physical condition, I pay close attention to a healthy diet, such as avoiding fatty food," she said. "Every weekend, I go cycling or go hiking with my son."

Zhang said her family members gave her great support.

"When my son was a little boy, I often took him along when I donated blood. I believe action is the best teacher," she said. "I feel quite happy when I see my son has grown to be a warmhearted youngster."

Yi Xiaomei, an official at the Yichang Blood Center, said there are more than 400 regular blood donors in the city. "They have made great contributions to blood donation in the city," Yi said. "Zhang Bi, as a typical example, tries her best to guarantee the quality and quantity of blood."

Zhang said donating blood is not only good for the recipient but improves her own mental and physical well-being. "I hope I can continue as long as my physical condition can meet the donor requirements," she said.