A group of researchers shared their hospital protocol in managing women of childbearing age with Rhesus D (RhD) negativity who received red blood cells (RBCs) that were RhD positive in an article recently published in Transfusion. This RhD mismatch typically triggers hemolytic disease of the fetus and newborn (HDFN).
What is HDFN?
Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated red blood cell disorder that occurs when a baby’s RBCs break down quickly, which is called hemolysis. HDFN is caused by a mismatch between a mother’s and her baby’s blood type (A, B, AB, or O) or Rhesus (Rh) factor (Rh-positive or Rh-negative) during pregnancy.
The authors of the study presented their hospital guidelines for the management of women of childbearing age who were RhD negative but received RhD positive RBCs. Should a mismatch be detected, the pathology/transfusion medicine specialist will carefully look through a checklist of eight items to ensure that patients fulfill all the criteria needed for RhIG to be released; most of these relate to patient demographics and treatment practicalities.
In some cases, RhIG may not be necessary. For example, patients who have 20% of their total blood volume replaced are deemed ineligible for this procedure as it raises the risk of hemolysis and the need for additional transfusions.
Read more about HDFN testing and diagnosis
The treating physician needs to be able to estimate the volume of RhD-positive RBCs that have been transfused. These can be easily calculated via several predetermined formulas. The goal is for physicians to know that they are administering RhIG at quantities sufficient to neutralize the RhD-positive RBCs already received.
Throughout treatment, laboratory testing should be readily performed to gauge clinical response and adjust treatment accordingly. For example, patients are advised to undergo an indirect antiglobulin test approximately once or twice a year following the blood product mismatch event.
“We have described our institutional protocol to prevent RhD alloimmunization in females of childbearing age who receive RhD-mismatched transfusions,” the authors wrote. “To our knowledge, this is the first guideline to be published directing the management of such cases.”
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