What should be performed after identifying mixed-field agglutination in a weak D test for a Rh-negative woman?

In cases where mixed-field agglutination is observed in a weak D test for an Rh-negative individual, performing a Kleihauer-Betke stain is a critical step. This test is used to identify the presence of fetal red blood cells in a maternal blood sample, which indicates whether there may be a fetal-maternal hemorrhage. In this scenario, the presence of mixed-field agglutination may suggest that there are both Rh-positive and Rh-negative cells present, which could be due to several reasons, including the possibility of Rh-positive fetal cells in the mother's circulation.

By performing the Kleihauer-Betke stain, you can quantify the amount of fetal blood in the maternal sample, which is essential for determining the appropriate dosage of Rh immunoglobulin (RhlG) that the mother may require. This helps prevent Rh sensitization in future pregnancies. Recognizing this mixed-field agglutination serves as an important indicator that warrants further investigation, making the Kleihauer-Betke stain a logical subsequent step to ensure proper patient management.

While it might seem appealing to report the patient as Rh positive, doing so without further investigation could lead to inappropriate treatment decisions and increased risk in future pregnancies. Administering RhlG