Detection of large fetal--maternal transfusions.

Two hundred consecutive Rh-negative women at risk of Rh sensitization were screened postpartum for large fetal--maternal transfusion by two acid elution techniques. The Nierhaus modification of the Betke-Kleihauer method and the Fetaldex test were compared. In 194 of 200 women, both procedures indicated the absence of significant fetal--maternal transfusion. In 6 women a large fetal--maternal hemorrhage was detected by the Betke-Kleihauer method and in 5 of these 6 by the Fetaldex test. The overall correlation between the two techniques was 99.5%. The Fetaldex test has advantages over the Betke-Kleihauer method and is well suited for routine use postpartum and for other situations where identification or quantitation of fetal cells is desirable.