Immunoradiometric assay of thyrotropin in plasma: its value in predicting response to thyroliberin stimulation and assessing thyroid function in amiodarone-treated patients.
We measured thyrotropin in plasma by an ultrasensitive immunoradiometric assay (TSH-IRMA, "Sucrosep," Boots-Celltech), before and after thyroliberin (TRH) stimulation, in 71 patients with suspected thyroid-function disorders. Thirty-three were taking amiodarone; none was receiving (anti)thyroid drugs. The patients were divided into four groups, according to their TSH response to TRH (as measured previously by conventional TSH-RIA) and the concentrations of thyroxin (T4) and triiodothyronine (T3) in their plasma. Observed ranges of plasma TSH-IRMA (milli-int. units/L) before and after TRH were: euthyroid (n = 20), 0.2-3.0 and 1.7-15.5; subclinically hypothyroid (n = 14), 4.3-18.5 and 20-75; hyperthyroid (n = 17), less than 0.09 and less than 0.09-0.4; and subclinically hyperthyroid (n = 20), less than 0.09-1.1 and less than 0.09-2.6. Evidently TSH-IRMA results for a single sample completely distinguish hyperthyroidism from euthyroidism. However, TSH-IRMA values may also be undetectable in subclinical hyperthyroidism. The TSH response to TRH can be predicted from basal TSH-IRMA results less than 0.09 or greater than or equal to 0.8 milli-int. unit/L, intermediate values can be associated with either a normal TSH response (euthyroidism) or a decreased TSH response (subclinical hyperthyroidism only). We advocate TSH-IRMA as the first diagnostic test of thyroid function for amiodarone-treated patients.
Wiersinga
W M
WM
Endert
E
E
Trip
M D
MD
Verhaest-de Jong
N
N
D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D001572:Benzofurans / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000139:chemically induced / Q000175:diagnosis; D007037:Hypothyroidism / Q000139:chemically induced / Q000175:diagnosis; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D013959:Thyroid Diseases / Q000139:chemically induced / Q000175:diagnosis*; D013960:Thyroid Function Tests / Q000379:methods*; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone
D001572:Benzofurans; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D000638:Amiodarone