ABSTRACT

In the Czech Republic, all pregnant women in their 1st trimester undergo the red blood cell antibody screening. The clinically significant alloantibody anti-K (Kell, KEL1) is diagnosed in about 0.1% of women (100 women a year in the Czech Republic). However, the fetuses are at risk of hemolytic disease only if the complementary antigen is present on their erythrocytes. This is the case of about 5% of them (5 fetuses a year) in contrast to 95% of them (95 fetuses a year) lacking the complementary antigen and thus not at risk of Hemolytic Disease of the Fetus and Newborn. The presence of the complementary antigen can be assessed noninvasively by KEL genotyping from cell-free fetal DNA circulating in the peripheral blood of pregnant women.