The best cutoff value of middle cerebral artery peak systolic velocity for the diagnosis of fetal homozygous alpha thalassemia-1 disease.

MCA-PSV > 1.30 MoM is the best cutoff value for the diagnosis of all degrees of fetal anemia from homozygous alpha thalassemia-1 fetuses. Because of its simplicity for interpretation and high efficacy, a cutoff value of MCA-PSV > 30 cm/s can also be used as an alternative marker for fetal anemia screening during 18 to 22 weeks of gestation.