D or anti-D!!! Unblocking the dilemma of blocking-D phenomenon using acid elution

Abstract

Maternal IgG antibodies directed against fetal red cells can cause hemolytic disease in fetus and newborn manifesting as anemia and jaundice. Sometimes, these antibodies are so strong that they encapsulate the antigens on neonatal red blood cells and result in erroneous laboratory findings when tested. A requisition for double volume exchange transfusion was received for a term,3.1 kg female baby with neonatal jaundice at day 2 of life, born to a multiparous woman. The neonate was typed as AB RhD negative and the mother as A Rh D negative. The maternal sample tested positive for Indirect antiglobulin testing showing presence of Anti-D with IgG titer of 128. The direct antiglobulin testing for baby was strongly (4 +) positive. The strong DAT result with negative RhD typing for the neonate indicated towards the Blocking-D phenomenon. We attempted to resolve the Blocked-D case using acid elution, which revealed the presence of D antigen on the eluted neonate's red cells. The report emphasizes the importance of appropriate blood typing for neonates to provide prompt adequate care as a team by the departments of Neonatology and Transfusion Medicine.

Keywords: Acid Elution; Blocking D phenomenon; Hemolytic disease- Fetus; Newborn; Rh D isoimmunization.