Because weak antibodies may give false negative results with red cells that have a weak expression of the corresponding antigen, there is a  risk associated with releasing donor blood before antibodies have been identified and donors have been antigen typed and found to be antigen-negative.

The risk is that a crossmatch-compatible donor unit may be positive for  the corresponding antigen resulting in a delayed hemolytic transfusion reaction (DHTR). The reaction may involve mild or severe hemolysis. Depending on the patient's overall condition, significant morbidity and even death may result. In the USA between 1976 and 1985, 26 patients died from DHTR compared to 158 from immediate HTR (Sazama, 1990).

Most DHTR are mild involving an unexplained drop in hemoglobin following transfusion and transient jaundice. However, some DHTRs produce severe hemolytic episodes:

  • Hillman NM. Fatal delayed hemolytic transfusion reaction due to anti-c + E. Transfusion 1979 Sep-Oct;19(5)548-51. [Medline ]

  • Cash KL, Brown T, Sausais L, Uehlinger J, Reed LJ. Severe delayed hemolytic transfusion reaction secondary to anti-At(a). Transfusion 1999 Aug;39(8)834-7. [Medline]

  • Sazama K. Reports of 355 transfusion associated deaths:1976 through 1985. Transfusion 1990;30:583-90. [Medline ]

Discussion Question

  1. Which signs, symptoms, and laboratory test results may indicate  hemolysis?