title: Time-resolved immunofluorometric assay for thyrotropin improved for enhanced functional sensitivity and clinical discrimination.
abstract: Modification of a new commercial time-resolved immunofluorometric assay for thyrotropin (DelfiaR hTSH Ultra) by prediluting samples, reducing tracer concentration, and increasing total reaction volume offered improved functional sensitivity of 0.005 mIU l-1 (20% between-assay CV) over the functional sensitivity limit of 0.014 mIU l-1 of the unmodified TSH assay. Serum TSH concentrations of 50 hyperthyroid patients and 24 clinically euthyroid patients with serum TSH < 0.1 mIU l-1 by a second generation immunoradiometric assay were analysed by both the original and modified TSH-IFMA method. The discrimination was better with the modified method, according to ROC-analysis (p = 0.027). In conclusion, these modifications enhanced functional sensitivity and improved the discriminatory power of the assay in separating hyperthyroid patients from euthyroid subjects with low TSH concentrations.
authors.affiliation: Department of Clinical Chemistry, University Central Hospital of Turku, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Taimela
authors.forename: P
authors.initials: P
authors.lastname: Koskinen
authors.forename: K
authors.initials: K
authors.lastname: Irjala
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin