Bloody tap amniocentesis: discrimination between fetal and maternal blood by means of hemoglobin electrophoresis.

Bloody amniotic fluid from amniocentesis or vaginal blood obtained in the late third trimester from 15 patients was analyzed for the presence of fetal blood by hemoglobin electrophoresis and Kleihauer-Betke tests. In addition, 15 experimentally formulated specimens were submitted for analysis. Where quantities were sufficient for parallel assay, the tests correlated 100%. Hemoglobin electrophoresis was an objective test for quantifying and accurately distinguishing the source of fetal-maternal bleeding.