title: 2nd-trimester maternal serum marker results are not altered by delayed analysis.
abstract: OBJECTIVE
  The goal of the study was to evaluate the significance of delayed laboratory analysis of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol for prenatal screening.
  
  
  METHODS
  Biochemical analysis of 30 consecutive biochemical screening specimens of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol was performed immediately upon arrival to the laboratory, 7 days later, and again 14 days after maternal blood was drawn. Differences among the results of the three sets of biochemical studies were evaluated by one-way analysis of variance for repeated measures.
  
  
  RESULTS
  No significant differences were found among the results of immediate assays as compared with those at a 7- or a 14-day delay for all three biochemical markers.
  
  
  CONCLUSIONS
  Our data suggest that up to a 14-day delay in the performance of the 2nd-trimester maternal serum biochemical screening assays will not alter the results significantly. The results of maternal serum screening are, thus, clinically valid even if the laboratory assays were performed several days after maternal blood was drawn.
authors.affiliation: Division of Reproductive Genetics, Department of Obstetrics and Gynecology, Hutzel Hospital, Detroit, Mich., USA.
authors.forename: B
authors.initials: B
authors.lastname: Feldman
authors.forename: E
authors.initials: E
authors.lastname: Dvorin
authors.forename: T
authors.initials: T
authors.lastname: Phillips
authors.forename: R L
authors.initials: RL
authors.lastname: Kramer
authors.forename: M P
authors.initials: MP
authors.lastname: Johnson
authors.forename: M I
authors.initials: MI
authors.lastname: Evans
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004964:Estriol / Q000097:blood; D005260:Female; D006801:Humans; D009436:Neural Tube Defects / Q000097:blood / Q000175:diagnosis*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D013997:Time Factors; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000509:alpha-Fetoproteins; D004964:Estriol