- Also known as extravascular hemolysis
- Generally mild and caused by antibodies to non-D antigens of the Rh system or to foreign alleles in other systems such as the Kell, Duffy, or Kidd antigens
- Following an ABO and Rh D-compatible transfusion, patients have a 1-1.6% chance of forming antibodies directed against foreign antigens in other systems. By the time significant amounts of the antibodies have formed, the donor RBCs have been cleared from circulation. Subsequently, the titers of these antibodies decrease over a period of time. A second exposure to these antigens with a subsequent transfusion triggers an anamnestic response against the foreign antigen. This response takes about 2 to 21 days after transfusion to reach significant levels hence why it is referred to as a delayed hemolytic transfusion reaction.
- Symptoms: malaise, jaundice, fever, Hct fails to rise, increased serum unconjugated bilirubin (as a result of Hbg breakdown)
- Diagnosis may be facilitated by the antiglobulin (Coombs) test
- Direct Coombs test detects the presence of antibodies on the membrane of red cells
- *however, this test cannot distinguish between recipient antibodies coated on donor RBCs and donor antibodies coated on recipient RBCs
- Treatment is primarily supportive
- Frequency: 1:12,000 transfusions
Copyright Information
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
