Rh Immune Globulin (RhIG) Workup Immunohematology Review 482
Prenatal evaluation
Postpartum evaluation
ABO & Rh (weak D not required). If Rh pos, woman isn’t candidate for RhIG.
Ab screen. (Don’t use IS or RT incubation or AHG with anticomplement activity.) If pos, ID antibody. If anti-D
present, woman isn’t candidate.
ABO & Rh, including weak D, on baby. If baby is Rh neg, mother isn’t candidate.
If baby is Rh pos, draw mother’s blood after delivery & perform rosette test to screen for large fetal bleed.
Mother’s RBCs incubated with anti-D. Anti-D coats fetal D-pos RBCs. Indicator D-pos RBCs added. Attach to
anti-D on fetal D-pos RBCs, forming rosettes.
If rosette test pos, quantitate fetal bleed by flow cytometry or Kleihauer-Betke acid-elution test. Fetal cells
resist acid elution; stain pink. Adult cells lose hgb; appear as “ghosts.”
