How I do it: An institutional protocol for the management of RhD negative women who receive RhD positive blood.

Background: RhD alloimmunization can result from blood transfusion or fetomaternal hemorrhage (FMH). Preventing alloimmunization in childbearing-age women with FMH via utilization of RhD immunoglobulin (RhIG) is well known; however, there are no established protocols for RhD-mismatched transfusions in emergent or traumatic settings. Here, we describe our hospital protocol for managing RhD negative women who receive RhD positive transfusions.

Methods: Pathology or Transfusion Medicine staff are notified of RhD-mismatched blood transfusions. Women with childbearing potential are evaluated by Obstetrics and Gynecology (ObGyn) to determine patients' childbearing desires and physical capabilities, as well as their ability to tolerate RhIG administration. Pathologists determine eligibility for therapy with RhIG: criteria include RhD negative females, <50 years old, without current or historical Anti-D, who have been transfused <20% of their total blood volume (TBV) with RhD positive blood.

Results: Management strategy depends on red blood cell volume (RBCv) transfused. Patients who receive an RBCv ≤20% of their TBV are eligible to receive RhIG, while an RBCv >20% makes individuals ineligible for prophylaxis with RhIG. Red cell exchange (RCX) is not offered at our institution, regardless of RBCv transfused. Women who receive RhIG should be screened for the development of antibodies using direct and indirect antiglobulin tests for 6-12 months posttransfusion. Future pregnancies of alloimmunized women should be carefully monitored.

Conclusions: Our therapeutic plan involves identifying eligible patients based on set criteria. This is the first published protocol to prevent RhD alloimmunization in females of childbearing age due to RhD-mismatched transfusions.