title: An enzyme immunoassay for determining 17alpha-hydroxyprogesterone in dried blood spots on filter paper using an ultramicroanalytical system.
abstract: BACKGROUND
  17alpha-hydroxyprogesterone has been used for the diagnosis of congenital adrenal hyperplasia (CAH) in the newborn period.
  
  
  METHODS
  A simple and rapid competitive ultramicro ELISA assay based on competition between 17-OHP-alkaline phosphatase conjugate and 17-OHP in blood specimens for a limited number of binding sites on specific polyclonal rabbit anti-17-OHP antibodies, has been developed for the measurement of 17-OHP in dried blood spots on filter paper. The assay buffer contains danazol to displace 17-OHP from steroid-binding proteins.
  
  
  RESULTS
  The 17-OHP assay was completed in 3 h, with a measuring range of 10-250 nmol/l. The intra- and inter-assay CV were 5.5-8.2% and 6.4-9.1%, respectively, depending on the 17-OHP concentrations. The recovery ranged from 98-103%. Of 3750 newborn samples collected on filter paper, 903 from the national neonatal screening program were analyzed, and the mean 17-OHP concentration was 12.2 nmol/l. Our assay showed high Pearson and concordance correlations with the commercially available ICN Neoscreen ELISA 17alpha-hydroxyprogesterone kit.
  
  
  CONCLUSIONS
  The analytical performance characteristics of our 17-OHP Neonatal UMELISA suggest that it can be used for the neonatal screening of CAH.
authors.affiliation: Department of Neonatal Screening, Immunoassay Center, 134 Street and 25 Avenue, Cubanacán, Playa, Havana, Cuba.
authors.forename: Ernesto Carlos
authors.initials: EC
authors.lastname: González
authors.forename: Neivis
authors.initials: N
authors.lastname: Marrero
authors.forename: Pedro Lucio
authors.initials: PL
authors.lastname: Pérez
authors.forename: Amarilys
authors.initials: A
authors.lastname: Frómeta
authors.forename: Orlando
authors.initials: O
authors.lastname: Zulueta
authors.forename: Darlenis
authors.initials: D
authors.lastname: Herrera
authors.forename: Luisa
authors.initials: L
authors.lastname: Martínez
authors.forename: Elisa
authors.initials: E
authors.lastname: Castells
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000097:blood* / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques / Q000295:instrumentation* / Q000379:methods*; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods*; D008851:Micropore Filters
chemical_list: D019326:17-alpha-Hydroxyprogesterone