APPLICATION OF THE APT TEST IN PRENATAL-DIAGNOSIS TO EVALUATE THE FETAL ORIGIN OF BLOOD OBTAINED BY CORDOCENTESIS - RESULTS OF 30 PREGNANCIES

This study aimed to set up a practical lab-side approach to discrimina te fetal from maternal blood in samples obtained by cordocentesis. To determine the fetal origin of the blood, a modified Apt test was appli ed to 30 cases of prenatal diagnosis. A change of colour of the fetal and adult blood during the procedure was the hallmark to assess fetal origin. At the end of 60 s of the test, fetal blood yielded a pink col our whereas adult blood was dark green-brown. The test was repeated in mixtures of fetal and adult blood. The results suggest that the modif ied Apt test is a practical, quick, inexpensive, and efficient test to determine the origin of blood samples obtained by cordocentesis. Howe ver, it-should be kept in mind that samples containing a mixture of bo th fetal and adult blood could also yield a fetal blood reaction. When maternal contamination is suspected, we propose that at least 30 meta phases from different slides should be counted. This could yield fetal as well as maternal chromosomes. (C) 1997 by John Wiley & Sons, Ltd.