title: Blocked D phenomenon and relevance of maternal serologic testing.
abstract: A blood requisition for double-volume exchange transfusion was received for a 2-day-old male child born to a 29-year-old multiparous female (P2002) referred to our institute having neonatal jaundice with encephalopathy; no maternal sample was received. the neonatal blood sample was typed as group A, D-, and the direct antiglobulin test (DAT) was strongly positive (4+) using the gel method. Mono-specific DAT showed the presence of IgG antibodies on neonatal red blood cells (RBCs). Acid elution and gentle heat elution (at 56°C) confirmed the presence of anti-D on neonatal RBCs. The baby received two exchange transfusions with group O, D-, packed RBCs compatible with his own serum. Later, on day 3, the neonate's mother was typed as group AB, D-, and her serum revealed the presence of alloanti-D, -C, and -S reactive in the anti-human globulin phase. The anti-D titer was 1024. this report highlights the "blocking" phenomenon caused by maternal anti-D in a case of hemolytic disease of fetus and newborn with a positive DAT.
authors.affiliation: MD, Assistant Professor (corresponding author), Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Sector 12, Chandigarh 160012, India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Jain
authors.affiliation: MD, Senior Resident, Department of Transfusion.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumawat
authors.affiliation: MD, FAMS, Professor and Head, Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors.forename: Neelam
authors.initials: N
authors.lastname: Marwaha
mesh_terms: D001803:Blood Transfusion / Q000379:methods; D003298:Coombs Test / Q000379:methods*; D004899:Erythroblastosis, Fetal / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D018029:Rho(D) Immune Globulin / Q000097:blood / Q000276:immunology*
chemical_list: C061961:RHO(D) antibody; D018029:Rho(D) Immune Globulin