The discovery of Bombay Blood Group was made more than 50 years ago with a patient who was admitted to KEM Hospital and required blood transfusions.  A sample of blood was sent to the Blood Bank for grouping as is the usual practice.  The red cells grouped like O group and hence O group blood was administered.  The patient developed haemolytic transfusion reaction, and therefore transfusion had to be stopped.

A detailed study of the patients blood revealed a rare genotype (blood group), which was neither ‘A’ nor ‘B’ nor ‘AB’ nor ‘O’.  Since the first case was detected in Mumbai (then Bombay), the blood group came to be called as Bombay Blood Group.  Blood from a Bombay Blood Group individual only should be transfused to a Bombay Blood Group patient.

It is now known that the precursor protein from which all blood groups are formed is termed as the ‘H’ Antigen.  The ‘H’ Antigen either translates into ‘A’ Antigen (the blood group is then called ‘A’) or it translates into ‘B’ Antigen (the blood group is then called ‘B’) or it translates into both ‘A’ and ‘B’ Antigens (the blood group is then called ‘AB’) or it remains as ‘H’ (the blood group is called ‘O’).  Earlier the detection of ‘O’ was on the basis of absence of both ‘A’ and ‘B’. In the case of Bombay Blood Group, there was an absence of the ‘H’ Antigen itself.  Therefore ‘A’, ‘B’, ‘AB’ and ‘O’ which are all different manifestations of ‘H’ are all alien for persons with Bombay Blood Group.  The Bombay Blood Group is termed as ‘OH’, which means absence of ‘H’.

Earlier, the Institute of Immuno Haematology (IIH) housed in the ICMR at K.E.M. Hospital, Mumbai, was the only referral laboratory for determining the Bombay Phenotype.  Samples from all over the country were sent to the IIH, which was the only place, which maintained a directory of persons detected with the Bombay Blood Group.  Here again, the presence or absence of  Rhesus Antigen would determine whether the person is Bombay Rh Positive or Bombay Rh Negative.  Today there are many laboratories and Blood Banks, which are able to detect and label Bombay Group.

If you are looking for Bombay Blood Group

If you are lookng for Bombay Blood Group, it is quite likely that the required units are not available in any Blood Bank. Click here for advice on the course of action to be taken.