title: Prenatal determination of the fetal RhD blood group by multiplex PCR: a 7-year Portuguese experience.
abstract: OBJECTIVE
  This is a retrospective study to evaluate the efficacy and accuracy of the multiplex polymerase chain reaction (PCR) amplification, for early detection of fetuses at risk for hemolytic disease, in the population living in Portugal, and to characterize the RhD-negative individuals at serologic and molecular level.
  
  
  METHODS
  2030 uncultured amniotic fluid samples and 2012 blood samples from the respective RhD-negative pregnant women were studied by multiplex PCR of intron 3/intron 4, exon 7 and 3'UTR. Amniocentesis was performed for a variety of medical indications. For quality control, serologic RhD blood groups were determined in the cord blood, after birth.
  
  
  RESULTS
  1361 fetal amniotic samples were RhD-positive (67%), 669 were RhD-negative. The average time for diagnosis was 2 days for uncultured amniocytes and the molecular versus serologic RhD typing (n = 809) had 99.5% concordance. Among the 2012 serologic RhD-negative mothers, 26 had an RhD-positive allele.
  
  
  CONCLUSIONS
  The multiplex PCR amplification used in this study was a rapid and accurate method to determine the RhD blood type in the population living in Portugal, being a great tool for management of pregnancies with fetuses at risk for alloimmune hemolytic disease. In this population, 1.3% of the serologic RhD-negative women have an RHD-positive allele.
authors.affiliation: Unidade Hematologia Molecular, Serviço Hematologia, Centro Hospitalar Coimbra, Portugal. uhm@hpc.chc.min-saude.pt
authors.forename: Janet Carvalho
authors.initials: JC
authors.lastname: Pereira
authors.forename: Ana Bela
authors.initials: AB
authors.lastname: Couceiro
authors.forename: Elizabete Maria
authors.initials: EM
authors.lastname: Cunha
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Machado
authors.forename: Gabriel Pinto
authors.initials: GP
authors.lastname: Tamagnini
authors.forename: Natália Prata
authors.initials: NP
authors.lastname: Martins
authors.forename: Maria Letícia
authors.initials: ML
authors.lastname: Ribeiro
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry*; D001788:Blood Grouping and Crossmatching; D004899:Erythroblastosis, Fetal / Q000517:prevention & control; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005787:Gene Frequency; D006801:Humans; D016133:Polymerase Chain Reaction; D011174:Portugal; D011247:Pregnancy / Q000097:blood*; D012189:Retrospective Studies; D012204:Rh-Hr Blood-Group System / Q000032:analysis* / Q000097:blood / Q000235:genetics
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen