Over the last two weeks, the “Bombay blood group”, a rare blood type, has been at the centre of attention in Mumbai’s healthcare scene. Demand for the blood type has coincidentally spiked at hospitals, but supply has been scarce.
Blood types, common & rare
The four most common blood groups are A, B, AB and O. The rare, Bombay blood group was first discovered in Mumbai (then Bombay) in 1952 by Dr Y M Bhende. Each red blood cell has antigen over its surface, which helps determine which group it belongs to. The Bombay blood group, also called hh, is deficient in expressing antigen H, meaning the RBC has no antigen H. For instance, in the AB blood group, both antigens A and B are found. A will have A antigens; B will have B antigens. In hh, there are no A or B antigens.
Rare in India, rarer globally
Globally, the hh blood type has an incidence of one in four million. It has a higher incidence in South Asia; in India, one in 7,600 to 10,000 are born with this type.
Testing for the group
To test for hh blood, an Antigen H blood test is required. Often the hh blood group is confused with the O group. The difference is that the O group has Antigen H, while the hh group does not.
If anyone lacks Antigen H, it does not mean he or she suffers from poor immunity or may be more prone to diseases. Because of rarity, however, they do face problems during blood transfusion.
Source: The Indian Express