Sept. 12, 2019

Over the last two weeks, demand for the “Bombay blood group” has coincidentally spiked at Mumbai’s hospitals, but supply has been scarce.


  • Names: H/H blood group is also known as Oh or the Bombay blood group.

  • Background: The rare, Bombay blood group was first discovered in Mumbai (then Bombay) in 1952 by Dr Y M Bhende.

  • What is it?
    • 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.

    • 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.

  • Transfusion limitations: The individuals with Bombay blood group can only be transfused autologous blood or blood from individuals of Bombay hh phenotype only which is very rare.

  • How rare is it?
    • 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.

    • This blood type is more common in South Asia than anywhere else because of inbreeding and close community marriages.