Analytical and Clinical Evaluation of Three Sensitive Thyrotropin Assays

Abstract

SUMMARY. Three sensitive assays (Behring, Organon and LKB-Pharmacia) for measurement of serum thyrotropin (TSH) were evaluated. All three assays showed good precision, sensitivity, linearity and for practical purposes negligible high dose hook effects. The correlations between the assays were excellent, but due to standardisation and/or matrix effects there were incomplete recoveries in two kits and the kits showed systematic differences of up to 20% in the TSH values obtained.The clinical utility of the three assays was investigated in patients with thyroidal and non-thyroidal illnesses and in healthy subjects with thyroxine binding abnormalities.According to the results of the analytical and clinical evaluation, all three kits are acceptable and reliable as first-line thyroid function tests. SAMPLES AND CONTROL SERASerum samples from all subjects and serum pools containing high (range 5-27 ml.I/L) and undetectably low concentrations of TSH were, after collection, stored in aliquots at -18°C.The human TSH reference preparations (WHO 1 st IRP (MRC: 68/38) and WHO 2 nd IRP (MRC: 80/558» were obtained from the

The sick euthyroid syndrome: changes in thyroid hormone serum parameters and hormone metabolism

“…Early studies on the Performance of sTSH assays in NTI patients showed normal sTSH concentrations (Spencer, 1986;Faber et al, 1987). By combination of the results of several studies (Alexander et al, 1984;Seth et al, 1984;Kirkegaard et a/., 1985;Semple et al, 1985;Bassett et al, 1986;Krcnning et ul., 1986;Gow et al, 1986;Squire & Gimlette, 1987;Bonte et al, 1989) sTSH measurements in 3421 NTI patients, not selected on severity of illness, could be collected. Only 79 or 2.3% had a suppressed sTSH result, a value to be expected on statistical grounds, because 95% confidence limits were used for the reference population, and consistent with the euthyroid status of these patients (Kaptein et a/., 1981b).…”