Prenatal Determination of Fetal RhD Type

Abstract
In the August 26 issue of the Journal, Bennett and colleagues describe the application of the polymerase chain reaction to determine the RhD genotype of fetuses by using DNA derived from chorionic villi and amniocytes1. The first set of oligonucleotide primers used (A1 and A2) yields a 136-base pair (bp) product common to the RhCcEe and RhD genes, whereas the second set (A3, a consensus primer, and A4, a primer specific for the 3' noncoding sequence of the RhD gene) yields a 186-bp product only in RhD-positive subjects.