title: 7 alpha-Biotinylated testosterone derivatives as tracers for a competitive chemiluminescence immunoassay of testosterone in serum.
abstract: Ring core-biotinylated testosterone tracers were synthesized with bridges of three different lengths connecting the biotin moiety to the steroid core (7 alpha-Cn-Bio-T, n = 3, 6, or 11). Together with a position 7-specific polyclonal anti-testosterone antibody, we used the 7 alpha-C11-Bio-T tracer to develop a novel, labeled-hapten competitive immunoassay for total testosterone in serum. (The C3 and C6 tracers proved to be not suitable for analogous immunoassays.) Enhanced chemiluminescence signal was generated by use of a second immobilized antibody and a streptavidin-horseradish peroxidase conjugate. The measuring range of the assay is 0.2-20.0 nmol/L, linearity of serial dilutions can be demonstrated, the lower detection limit is 0.125 nmol/L, and the interassay imprecisions are 13-16%. Accuracy determinations in mass spectrometry-controlled reference specimens showed a mean recovery of 95%. In addition, the assay shows low cross-reactivities, demonstrating the favorable specificity of the combination of a "nearly native" tracer with a position analog antibody. The optimized steric structure and the long spacer arm of the biotinylated testosterone tracer make this chemiluminescence assay well-suited for measuring total testosterone concentration in serum.
authors.affiliation: Institute of Clinical Chemistry and Pathobiochemistry, Klinikum rechts der Isar, Technical University Munich, Germany. peter.luppa@edv1.klinchem.med.tu-muenchen.de
authors.forename: P
authors.initials: P
authors.lastname: Luppa
authors.forename: C
authors.initials: C
authors.lastname: Brückner
authors.forename: I
authors.initials: I
authors.lastname: Schwab
authors.forename: S
authors.initials: S
authors.lastname: Hauck
authors.forename: S
authors.initials: S
authors.lastname: Schmidmayr
authors.forename: C
authors.initials: C
authors.lastname: Birkmayer
authors.forename: B
authors.initials: B
authors.lastname: Paulus
authors.forename: H
authors.initials: H
authors.lastname: Hauptmann
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007118:Immunoassay; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity; D013739:Testosterone / Q000031:analogs & derivatives / Q000097:blood*
chemical_list: D013739:Testosterone