Clinical application of the Kleihauer-Betke test.

A prospective study was performed to investigate the benefit of serial quantitation of fetomaternal hemorrhage with the Kleihauer-Betke test for the prediction of neonatal/maternal outcome in pregnancies at risk for such bleeding. Of 65 patients, 14 (22%) had a positive Kleihauer test. Six of these women (43%) had evidence of placental abruption. Neonatal anemia (hematocrit < 48%) was present in only 2 of the 14 patients with a positive Kleihauer test (14%). Morbidity in the newborn correlated with gestational age at delivery, not with neonatal hematocrit. Maternal morbidity was not associated with a positive test. We conclude that Kleihauer-Betke testing is of limited value in patients at risk for fetomaternal hemorrhage.