Measurement of fetal cells in the maternal circulation.

There is evidence that the quantitation of fetal-maternal hemorrhage may be useful in reducing some of the RhoGAM failures in preventing Rh sensitization. The Betke-Kleihauer technique is a well-established method that has been used to estimate the amount of transplacental hemorrhage. Recently, a kit (Fetaldex) has become available for use in the detection and quantitation of fetal-maternal hemorrhage. Using control blood smears, we compared the results of the Fetaldex kit with those results obtained by the Betke-Kleihauer technique. The data indicate that the Fetaldex method is as accurate as the Betke-Kleihauer technique in detecting and measuring fetal red cells in the maternal circulation.