title: Ultrasensitive two-site immunometric assay of human lutropin by time-resolved fluorometry.
abstract: A rapid, sensitive two-site immunometric assay for human lutropin (LH), with two monoclonal antibodies directed against the beta subunit, has been developed with time-resolved fluorescence as the detection principle. The cross-reactivities with human thyrotropin and human follitropin are negligible and that with human choriogonadotropin is 1% in the standard two-step protocol. Free beta subunits of LH are also detected. Besides the standard procedure (45 + 15 min), more rapid alternative protocols (15 + 15 min or 30 min in one step) have also been evaluated. The minimum detectable dose per well is approximately 1 amol (10(-18) mol), corresponding to less than 0.01 int. unit/L, for a sample volume of 25 microL and less than 0.001 int. unit/L for 200-microL samples. The intra- and interassay CV is less than 6% for LH concentrations from 0.2 to 250 int. units/L. With 200-microL sample volumes, intra-assay variation is less than 6% at 0.04 int. unit/L and interassay variation is 7% at 0.05 int. unit/L. The very high sensitivity and reproducibility of the presented method enables assay of low prepubertal and of suppressed LH concentrations, and represents a clear improvement over currently available immunoassays.
authors.affiliation: Wallac Immunodiagnostic Research Laboratory, Turku, Finland.
authors.forename: K S
authors.initials: KS
authors.lastname: Pettersson
authors.forename: J R
authors.initials: JR
authors.lastname: Söderholm
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D002675:Child, Preschool; D005260:Female; D015200:Fluoroimmunoassay; D006801:Humans; D007700:Kinetics; D007986:Luteinizing Hormone / Q000097:blood* / Q000652:urine; D008297:Male; D008598:Menstruation / Q000097:blood; D011628:Puberty, Delayed / Q000097:blood
chemical_list: D000911:Antibodies, Monoclonal; D007986:Luteinizing Hormone