This case concerns a common scenario in the transfusion service (TS) laboratory, the detection of anti-D at delivery in a female who has received Rh immune globulin (RhIg) during pregnancy.
Distinguishing between passive and immune anti-D is important clinically:
- If passive anti-D is misinterpreted as immune, RhIg prophylaxis may be omitted leading to D sensitization.
- If immune anti-D is misinterpreted as passive, appropriate follow-up of the antibody may be curtailed putting the fetus at risk.
Unfortunately, differentiating between immune and passive anti-D is often impossible.
This case study presents an opportunity to review perinatal testing programs and the crucial role of RhIg in preventing hemolytic disease of the fetus and newborn (HDFN) due to anti-D. The case also examines practical aspects of routine serologic testing involving neonates and women who have received RhIg during pregnancy.
In brief, the case will:
- Guide participants through laboratory findings that need to be interpreted and resolved;
- Examine current best practices in perinatal testing programs;
- Review the characteristics of RhIg and its use in pregnancy;
- Review and investigate key issues associated with detection of anti-D in women who have received antenatal RhIg;
- Discuss crossmatch and LIS policies related to RhIg-derived passive anti-D.