Bombay blood group is a rare one it is found only in four out of one million people. It is so rare that there are only 400 registered donors for this blood group in India, which is home to over 1,354,051,854 people. But how did Bombay Blood get its name?
Blood groups were discovered in 1900 by Australian scientist Karl Landsteiner. They come in four types A, B, AB and O. The blood group actually indicates the antigens found on the red blood cells. Broadly there are two types of antigens A and B. Blood with A antigen is called A group while blood with B antigen is called B group. If the blood has both antigens then it is called AB if it has neither then it is called the O group.
In 1952 a trio of doctors at Bombay KEM Hospital came across a patient whose blood would not match with A, B, AB or O. It turns out that antigens A and B have an ancestral antigen called H and all three of them A, B and H were missing at KEM hospital patients blood. After trying 160 unsuitable donors, finally found a matching donor, since he was from Bombay they called it the Bombay blood group.
A person with the Bombay blood group is a universal donor but they can accept only from the same group. Since sometimes they can get erroneously labelled as the O group. A specific testing for antigen H will confirm if it is indeed the Bombay blood group.