RESUMO
H-deficient phenotype individuals with absent or weak anti-H activity may remain undetected on standard routine blood grouping. We report a case of a 59-year-old-man presented with symptomatic anaemia secondary to upper gastrointestinal bleed with haemoglobin level of 68 g/L who required two units of packed red blood cells. He was previously grouped as O Rh D positive and had a history of uneventful multiple blood transfusions. His latest pre-transfusion investigations showed ABO discrepancy between forward and reverse blood grouping, pan-agglutination in both antibody screening and identification with negative direct Coombs test and autocontrol. Further testing including anti-H lectin test and saliva secretor study confirmed that the patient blood group was para-Bombay B RhD positive. This case highlights that the para-Bombay phenotype can be mistakenly labelled as "O" if further investigations are not performed.
