What is the patient’s blood group?

O+

Is there an ABO discrepancy?

No

How would you interpret the antibody identification panel?

There is a pan-reactive antibody which reacts with all cells, except the patient’s own cells. This excludes an autoantibody seen in warm autoimmune haemolytic anaemia. The antibody reacts at 37 degrees, ruling out a cold autoantibody. The patient is blood group O, which raises the suspicion of a Bombay blood group.

What test is needed to confirm the diagnosis?

Test the patient’s red cells with anti-H lectin (an extract of the plant Ulex europaeus). If there is no reaction, it confirms the diagnosis of a Bombay blood group (O_h). Patients with a Bombay blood group are genetically hh, and do not express the H antigen at all. They have a potent, naturally-occurring anti-H antibody, which binds to all cells with a H antigen (any patient why is HH or Hh). The H antigen is required for phenotypic expression of ABO genes, hence all patients who are hh are phenotypically typed as group O. The Bombay blood group is extremely rare, occurring in 1 in 10,000 Indians and 1 in 1.000.000 Caucasians (Priye et al., 2015).

Should this patient require a blood transfusion, what type of blood should be ordered for her?

Bombay patients can only receive Bombay blood. This is because the anti-H in their plasma can react with H antigens present in A, B or O individuals, causing haemolytic transfusion reactions. Autologous blood donation can be considered in patients without anaemia who may require blood transfusion in the future.