A 40 year old female patient presents with excessive bleeding. Patient gives a history of road traffic accident 5 hours ago and had a lacerated wound on lower back region. Blood grouping test reveals presence of Anti A antibody, Anti B antibody, Anti H antibody and Anti Rh D antibody in the serum. The blood group of this patient is?: (A) O positive, (B) O negative, (C) AB positive, (D) Bombay blood group
Answer is D. → Apart from A< B and O RBC of type O contains large amount of another antigen called H substance.
→ H substance is genetically different from ABO but is a precursor of A and B antigens.
→ An O group individual who inherits A or B genes but fails to inherit H gene from either parent is called Oh phenotype or Bombay blood group.