title: A comparison of two immunoassay methods for the measurement of maternal serum placental growth factor in early pregnancy.
abstract: OBJECTIVE
  To compare the DELFIA Xpress and Quantikine ELISA placental growth factor (PlGF) immunoassay platforms by analysing the same set of early first-trimester maternal serum samples from cases with trisomy 21 and euploid controls.
  
  
  METHODS
  Thirty-seven trisomy 21 cases and 243 euploid control serum samples, drawn at 8(+0) to 10(+6) weeks of gestation, were reanalysed by Quantikine PlGF ELISA following original analysis on the DELFIA Xpress platform.
  
  
  RESULTS
  PlGF levels increased with gestation in the euploid controls when measured on both platforms, although raw levels were in general lower on the DELFIA Xpress. After conversion to multiples of the median (MoMs), PlGF was increased in trisomy 21 cases when measured on the DELFIA Xpress platform (euploid: 1.00 MoM, trisomy 21: 1.32 MoM, p < 0.0001) but unchanged when measured on the Quantikine ELISA (euploid: 1.01 MoM, trisomy 21: 1.06 MoM, p = 0.84).
  
  
  CONCLUSIONS
  Discrepancies exist in the measurement of PlGF when performed on these different platforms, which may to some extent contribute to the inconsistencies found in the literature with regard to PlGF in trisomy 21 pregnancies.
authors.affiliation: Prenatal Screening Unit, Department of Clinical Biochemistry, King George Hospital, Goodmayes, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Cowans
authors.forename: M
authors.initials: M
authors.lastname: Kisanga
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: K
authors.initials: K
authors.lastname: Spencer
mesh_terms: D000328:Adult; D004314:Down Syndrome / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005865:Gestational Age; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D000072483:Placenta Growth Factor; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods
chemical_list: C000608036:PGF protein, human; D011257:Pregnancy Proteins; D000072483:Placenta Growth Factor