title: Ability of two new thyrotropin (TSH) assays to separate hyperthyroid patients from euthyroid patients with low TSH.
abstract: We evaluated the ability of new thyrotropin (TSH) assays to separate hyperthyroid (n = 50) patients from clinically euthyroid subjects with low TSH values (nodular goiter, n = 20, and nonthyroidal illness, n = 22). Only patients whose serum TSH was < 0.1 mIU/L by immunoradiometric assay were included. We used a new immunofluorometric method based on time-resolved fluorescence (TR-IFMA) and a new immunochemiluminometric assay (ICMA) to measure TSH in serum. Although the differences between the hyperthyroid patients and the euthyroid patients differed from each other by both methods (P = 0.0012 for TR-IFMA and P < 0.0001 for ICMA), there was no cutoff point that could definitely separate the groups. Thus, it is not possible to draw any definite conclusions on whether a patient is hyperthyroid or not, solely on the basis of TSH concentration measured with these new TSH assays.
authors.affiliation: Department of Clinical Chemistry, University Central Hospital of Turku, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Taimela
authors.forename: R
authors.initials: R
authors.lastname: Tähtelä
authors.forename: P
authors.initials: P
authors.lastname: Koskinen
authors.forename: P
authors.initials: P
authors.lastname: Nuutila
authors.forename: J
authors.initials: J
authors.lastname: Forsström
authors.forename: S
authors.initials: S
authors.lastname: Taimela
authors.forename: S L
authors.initials: SL
authors.lastname: Karonen
authors.forename: M
authors.initials: M
authors.lastname: Välimäki
authors.forename: K
authors.initials: K
authors.lastname: Irjala
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D015200:Fluoroimmunoassay / Q000706:statistics & numerical data; D006044:Goiter, Nodular / Q000097:blood / Q000175:diagnosis; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000175:diagnosis*; D007118:Immunoassay / Q000706:statistics & numerical data; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin