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Sangeeta Pathak: The Bombay Blood Group as a Very Rare Phenotype
Sep 1, 2026, 16:15

Sangeeta Pathak: The Bombay Blood Group as a Very Rare Phenotype

Sangeeta Pathak, Senior Director and Head at Max Healthcare, shared a post on LinkedIn:

What is a Bombay blood group:

The Bombay blood group (Oh or hh) is a very rare blood-group phenotype first described in Bombay (Mumbai), India.

People with the Bombay phenotype lack the H antigen on their red blood cells.

The H antigen is the precursor needed to form the A or B antigens.

Therefore, even if their genes are for A or B, their red cells do not express A or B antigens, so routine ABO typing can misleadingly appear to show group O.

They also usually have anti-H antibodies in their plasma, in addition to anti-A and anti-B.

Because ordinary group O blood contains H antigen, a person with Bombay phenotype generally cannot safely receive ordinary O blood.

They need compatible blood from another Bombay-phenotype donor.

How common is it in India?

The Bombay phenotype is estimated to occur in approximately 1 in 10,000 people in India, or about 0.01% of the Indian population.

Its frequency is higher in some regions and communities.

For comparison, worldwide it is much rarer – roughly 1 in 1,000,000 people, although estimates vary by population.

In short:

Bombay blood group is equal to hh/Oh phenotype plus absence of H antigen plus anti-H antibody plus approximately 0.01% (1 in 10,000) in India.

Very happy to be featured in ‘MedInsider’ a monthly news read by Max Hospitals for – Doctors setting benchmarks by managing challenging medical cases extraordinarily.

Do read the story given below related to Bombay blood group .”

Sangeeta Pathak

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