title: Noninvasive determination of fetal RhD status using fetal DNA in maternal serum and PCR.
abstract: OBJECTIVE
  Because prenatal testing of fetal RhD status by amniocentesis carries small yet finite risks to the fetus and mother, this study sought to determine whether fetal DNA in maternal serum could be used to detect fetal RhD status by polymerase chain reaction (PCR).
  
  
  METHODS
  A retrospective analysis was made of frozen serum specimens from 20 sensitized RhD-negative pregnant women (ranging from 15.0 to 36.0 weeks' gestation) who were confirmed by serology at birth to have been carrying RhD-positive fetuses. Eleven serum specimens from RhD-negative individuals served as controls. DNA was isolated from serum and used in two PCR-based methods to detect a 99 base pair (bp) DNA fragment specific for the RhD gene and a 113 bp fragment specific for the RhCE gene as control.
  
  
  RESULTS
  Overall, in 14 (70%) of 20 RhD-positive fetuses the 99 base pair RhD-specific PCR product was detected. There was no false positive detection among the 11 control serum specimens.
  
  
  CONCLUSIONS
  The results illustrate the ability to detect fetal RhD sequences in maternal serum of sensitized women. Moreover, the findings demonstrate that fetal single-gene disorders can be detected prenatally by using DNA isolated only from maternal serum.
authors: Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas 77030, USA. bischoff@bcm.tmc.edu
authors: F Z
authors: FZ
authors: Bischoff
authors: D D
authors: DD
authors: Nguyen
authors: D
authors: D
authors: Marquéz-Do
authors: K J
authors: KJ
authors: Moise
authors: J L
authors: JL
authors: Simpson
authors: S
authors: S
authors: Elias
mesh_terms: D001788:Blood Grouping and Crossmatching / Q000379:methods; D004247:DNA / Q000097:blood*; D005260:Female; D005312:Fetal Blood; D006801:Humans; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012189:Retrospective Studies; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D012680:Sensitivity and Specificity
chemical_list: D012204:Rh-Hr Blood-Group System; D004247:DNA