Direct solid-phase time-resolved fluoroimmunoassay of 17α-hydroxyprogesterone in serum and dried blood spots on filter paper

R. R. Gonzalez, O. Maentausta, J. Solyom, R. Vihko

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We describe a direct, solid-phase time-resolved fluoroimmunoassay (TRFIA) for measuring 17α-hydroxyprogesterone (17OHP) in serum and blood spots on filter paper. We used 17OHP-3-carboxymethyloxime (17OHP3CMO) coupled to polylysine as the label, which enabled incorporation of up to 34 atoms of europium per molecule of 17OHP, for a very high specific activity. The assay is based on competition between labeled 17OHP3CMO and 17OHP in blood specimens for polyclonal rabbit anti-17OHP antibodies. The antibody-label complex is separated by binding to anti-rabbit antibodies coated onto microtiter strips. The assay buffer contains danazol to displace 17OHP from steroid-binding proteins in serum. For serum samples, the assay is accomplished in 1 h of incubation at room temperature. The blood spot assay with filter paper discs involves incubation overnight at 4°C. Results for both types of specimens from the same subjects correlated well. The lowest measurable concentrations of 17OHP (nmol/L) were 0.10 (3 SD) and 0.75 (3 SD) for serum and dried blood on filter paper, respectively. Intra- and interassay CVs were about 5-15% for both types of samples.

Original languageEnglish
Pages (from-to)1667-1672
Number of pages6
JournalClinical chemistry
Issue number9
Publication statusPublished - Oct 19 1990


ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

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