Blood Group: H

Common: Extremely rare

Causes HDN: Yes

Critical Titer: 


2013 saw the first recorded case of HDN due to anti-H in a Bombay phenotype mother [2]. Previously it was only theory saying that anti-H could exist and cause HDN [1]. The infant had a negative direct coombs test, but signs of hemolysis. His bilirubin levels were high enough to warrant an exchange transfusion at 33.2 mg/dL, but compatible blood could not be found for him, so he was managed with phototherapy only. Anticipating anemia and hyperbilirubinemia in mothers with the Bombay phenotype would allow earlier notification of transfusion services so they can find appropriate blood before it is needed. This would help to optimize neonatal care and outcome. 


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