Bombay Blood Group or h/h blood group: One of the Rarest Blood Type

Bombay blood group is named after Bombay aka Mumbai.

You might be aware of A, B & O blood groups. Moreover, there is a blood group which is so rare that it is found only 1 in every 250,000 people (in 0.0004% world population). This blood type is named as Bombay Blood Group.

To understand Bombay Blood Group clearly, we need to know about ABO Blood grouping system.

Blood Typing

Blood typing is a method to determine what type of blood you have. This test is essential for donating & receiving blood.

Not all the blood groups are compatible with each other. Receiving incompatible blood could trigger a dangerous immune response or even death.

The Blood Groups

Blood group is determined by what kind of antigens your red blood cells have on their surface.

Antigens are substances that help your body differentiate between its own cells and foreign ones. If your body thinks a cell is foreign, it will aim to destroy it.

Blood group Inheritance
Blood group Inheritance

Your blood group is determined genetically.
You inherit one allele from your father and one form your mother for your blood group.

O allele is recessive while A & B allele shows co-dominance with each other.

The ABO Blood Grouping System categorised your blood in four types.

Blood GroupsAntigens in RBCsAntibodies in Plasma
AA-antigen, H-antigenAnti-B
BB-antigen, H-antigenAnti-A
ABA-antigen, B-antigen, H-antigenNone
OH-antigenAnti-A, Anti-B
BombayNoneAnti-A, Anti-B, Anti-H
ABO Blood Type

These Blood types are further organised by Rh factor:

  • Rh-positive: People with Rh+ve blood have Rh antigens on the surface of their RBCs. People with Rh+ve blood can receive Rh+ve or Rh-ve blood.
  • Rh-negative: People with Rh-ve blood do not have Rh antigens on the surface of their RBCs. People with Rh-ve blood can receive only blood that is also Rh-ve.

Blood Group Compatibility Table

Blood TypeCan Donate toCan Receive from
A+A+, AB+A+, A-, O+,O-
B+B+, AB+B+, B-, O+, O-
O+O+, A+, B+, AB+O+, O-
A-A+, A-, AB+, AB-A-, O-
B-B+, B-, AB+, AB-B-, O-
AB-AB+, AB-AB-, A-, B-, O-

*Above Table doesn’t include Bombay Blood Group.

  • Blood group AB+ has none of the antibodies, so it can accept blood from all types. Therefore, AB+ blood group is called as Universal Recipient.
  • Blood group O- does not have any antigen in RBCs, so it can donate to all other blood groups. Therefore, O- blood group is called as Universal Donor.

Blood Group Compatibility Table

Blood typeCan Donate toCan receive from
Bombay+Bombay+Bombay+, Bombay-
Bombay-Bombay+, Bombay-Bombay-

Actually, Bombay negative blood group is truly a universal donor as it can donate blood to all other blood groups (while O- cannot donate to Bombay blood group).

Mistaken as O blood group

Bombay blood group is usually mistaken as O blood group. It is because the presence and absence of antigen/antibodies A/B and Rh alone is tested in the blood.

O blood group and Bombay Blood group can be differentiated by a specific test for H-antigen.

Do you have Bombay Blood Group?

We all should know our blood group, it is better to avoid chaos in an emergency situation. Additionally, if you have O blood group, make sure it’s not Bombay blood group.

Rakesh Barwar
Rakesh Barwar
Founder and Editor-in-Chief of The Last DNA. My passion for technology and biotechnology give rise to this awesome site. I write articles that can be easily understood by a majority of people, therefore making biotech simple and interesting!


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