On top of that, donors must have type O or A blood.
OneBlood is working with other groups, as well as the American Rare Donor Program, an organization that searches worldwide for rare blood donors, to find matches for Zainab, as she will need blood transfusions for the foreseeable future. This means that both the parents of the donors must be from Pakistan, India or Iran and the blood type should be either "O" or "A".
Additional donors are still needed, OneBlood says, as Zainab will need blood transfusions for the foreseeable future.
The two-year-old from South Florida, Zainab suffers from Neuroblastoma, a cancer that grows from immature nerve cells surrounding the adrenal glands that affects children of five years of age or under.
A worldwide search is underway to find some of the rarest blood in the world to help a 2-year-old Florida girl battling cancer.
OneBlood says that Zainab's blood is extremely rare because she is missing a common antigen that most people carry in their red blood cells. Because the antigen is so common, it makes it hard to find blood donors who are lacking it as well, Forbes said. And more than 1,000 people who are of Iranian, Indian or Pakistani descent have donated blood to be tested, Forbes said.More news: Police recommend Israeli PM Benjamin Netanyahu be indicted for bribery
And even within these ethnic groups, fewer than 4% have the genetic variation.
Around 800 children in the USA are diagnosed each year with the disease and most are diagnosed when they are younger than five.
Dr Bright further explained, "She's going to need to be completely supported by blood donations in order to survive the cancer treatment in order to kill this cancer".
So far three donors have been found, including one in England, but doctors estimate they will need at least seven to 10 people continuing to contribute throughout the course of Zainab's treatment. All donations must be coordinated in advance to ensure compatibility.
Visit www.oneblood.org/zainab for more donation information. "My daughter's life very much depends on the blood, so please donate the blood for my daughter".
OneBlood, a not-for-profit organisation, is offering to co-ordinate compatibility testing anywhere in the world.