The Fifth Blood Type: Oh

Bombay Phenotype: The Rare Blood

Bombay Phenotype: The Rare Blood

You might encounter this very rare blood type and you must take note who can donate to a person with this rare blood type. Another royal blood, Oh can only receive blood from persons with Oh blood types as well.

H antigen deficiency, dubbed as the “Bombay phenotype” (h/h or Oh) is found in 1 of 10, 000 individuals. By the name, the blood type originates in Bombay, India (now known as Mumbai) but is not only limited to people living in India. Actually, some Europeans have been recorded to have the same blood type as well. The blood type was discovered in a very intriguing way when an Indian patient was transfused with a compatible blood type. But a very different reaction in the blood was found. Same was true when other blood types were used. The red blood cell of the patient appeared to lack all of the ABO blood group antigens with an additional antigen discovered.

Bombay Phenotype Components

The different Bombay Phenotype is an H antigen deficient blood type. H antigen is contained in all RBCs for normal ABO blood group (A, B, AB, and O) and plays a vital role in the production of the other antigens in the ABO blood group. But because Oh is deficient, it cannot produce the other antigens.

This blood type is created after two recessive alleles of the H gene. This can happen when both parents are of incomplete H deficiency like AO or AB.

Who Can Donate?

Since persons with Bombay Phenotype don’t have all the other antigens in the ABO blood group, these persons cannot receive blood from donors with blood types A, B, AB and O. Else, agglutination or clumping of bacteria or red blood cells in the presence of an antibody. So, donors should be sought first among blood relatives. Additionally, Red Cross also maintains a list of persons with rare blood who can donate.

However, persons with Bombay Phenotype can be a donor to any of the other ABO blood types because A & B antigens are produced by the H antigens.



  1. jacinth1215 · · Reply

    I do not wish to have this type of Blood.. Scary!

    1. Really scary, jacint1215. You should have your blood type checked already. Like mine, I have O positive.

      1. jacinth1215 · ·

        Well, Actually I dont know mine.. But who knows I’ve got blood type Z hahahaha

      2. Then that will be the weirdest. 🙂

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