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Sumyea Kabir: The Hidden Risk of Bombay Blood Group

Sumyea Kabir/LinkedIn

Apr 13, 2026, 11:31

Sumyea Kabir: The Hidden Risk of Bombay Blood Group

Sumyea Kabir, Assistant Professor at Zainul Haque Sikder Women’s Medical College and Hospital, shared a post on LinkedIn:

”Bombay Blood Group (Oh): When ‘O’ Is Not O
A rare phenotype. A common mistake. A potentially fatal outcome.

During my residency at Bangladesh Medical University, I encountered 5 confirmed cases of Bombay blood group (Oh)—a powerful reminder that assumptions in blood grouping can cost lives.

The Dangerous Assumption:

Appears as O group on forward typing
considered universally compatible

O blood transfusion can cause acute hemolytic reaction

Apparent O is not equal to Safe O

Why named as ‘Bombay’ Blood Group?:

First reported in 1952 in Bombay (Mumbai), India
Discovery led to identification of absence of H antigen
A landmark chapter in immunohematology—still clinically relevant today

What the Textbooks and Guidelines Say (Very Clearly):

Mollison’s Blood Transfusion:

Forward grouping alone is dangerous
Reverse grouping discrepancy is the key diagnostic clue
Anti-H must be considered in apparent O groups

Denise Harmening:

Bombay phenotype produces strong anti-H
Incompatible with all ABO groups, including O

AABB Technical Manual:

Both forward and reverse grouping are mandatory
ABO discrepancies must be resolved before issue
Rare blood groups must be documented and traceable

WHO Blood Safety Guidance:

Emphasizes accurate grouping and antibody detection
Strongly supports rare donor identification and registries

Classic Diagnostic Pattern (Do Not Miss!):

Forward: anti-A negative | anti-B negative
Reverse: A, B and O cells all positive
Anti-H lectin: negative
Diagnosis: Bombay blood group

Clinical Reality:

Cannot receive A, B, AB or O blood
Requires Bombay phenotype donor only
Missed diagnosis leads to life-threatening reaction

What We MUST Build (System Responsibility):

Permanent flagging of rare phenotypes
Counseling and retention of rare donors
24/7 emergency donor contact lists
Inter-hospital and regional networking
National rare blood donor registry

Final Take-Home Message:

No reverse grouping means no safe transfusion
Bombay blood group is rare—but errors should never be

From MBBS textbooks to tertiary hospitals, the message is the same:
Details save lives in transfusion medicine.

Reference Figure (A)Shows agglutination reaction of the blood sample taken from an individual with an O-positive blood group, showing agglutination with anti-A and anti-B antisera, but no agglutination with anti-D and anti-H antisera.

(B) Represents the patient’s blood sample with an O-positive Bombay blood group which shows agglutination with anti-A, anti-B, and anti-H antisera, but no agglutination with anti-D antisera.”

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