Only a small fraction of Israelis have Type AB blood, but there are 960 people in Israel who have even rarer kinds - blood free of antigens that would harm hundreds of sick people whose blood has developed antibodies against them. These 960 are the potential donors for those who have anemia and need blood. Since 1970, the national blood lab for characterizing and identifying these rare blood groups has been operating, initially as part of the Health Ministry's central labs and since 1995 as part of Magen David Adom's Blood Services. To mark International Blood Donation Day Thursday, MDA is holding its second conference of rare-blood-type donors. One of the guests will be the mother of a 12-year-old Jewish boy from the center of the country who suffers from the genetic disease thalassemia, which causes severe anemia and requires frequent transfusions. Getting frequent transfusions of donated blood can result in the development of antibodies that cause serious reactions when blood with such antibodies is infused. The boy was found to have five different antibodies that made it very difficult to find a suitable donor. This combination of antibodies gave him a one in 10,000 chance of getting a suitable blood donation. However, MDA's Blood Services has gone to extraordinary lengths to locate donors for him, and now he is able to live a normal life, go on hikes and even enjoy sports activities. The MDA lab, headed by deputy Blood Services director Dr. Vered Yahalom, tests patients who need rare blood to determine what antibodies they have and identifies potential donors whose blood is suitable and will not cause harm. Blood type is determined by genetic inheritance. Because Israel is a country of immigration from all over the Diaspora, and the population includes a wide variety of non-Jews as well, there are over 250 different sub-types of blood, many of them rare. Unlike ordinary donated blood, which is not frozen due to the high cost of processing (NIS 1,140 per unit) and because there is an ongoing supply, rare types are often frozen and can be stored for years. But they can be used within only 24 hours of being defrosted, said Yahalom. Last year, 73 units of rare blood were defrosted and supplied to patients suffering from anemia who had developed antibodies and could not accept regular blood. In addition, another 2,767 units of fresh rare blood were provided. MDA has to struggle for each pint of blood, as many Israelis are reluctant to face a disposable needle. Only 4.3 percent of the public donate blood. The Israel Defense Forces, said Yahalom, used to provide 33% of the supply, but today the figure has dropped to 24%. The IDF no longer provides an incentive such as taking the day off. "But where there are highly motivated commanders who provide a personal example, there are numerous units with high donor rates," she said, adding that more must be done to educate the public, including the military, on the importance of donating blood - which itself provides blood insurance for oneself and one's immediate family.