Evaluation of a new chemiluminescence technique for human thyrotropin (BeriLux hTSH): diagnostic value of five immunometric assay methods.
A new commercially available human thyrotropin immunochemiluminometric assay (ICMA) kit was evaluated. The BeriLux assay (Hoechst Co., Germany) was compared with two other non-radioisotopic methods (AIA-1200 and IMx) and two other immunoradiometric assays (RIA-gnost TSH IRMA and EIKEN IRMA kits) in 32 normal subjects and 104 patients with Graves' disease, divided into seven groups: 1) untreated hyperthyroidism; 2) hyperthyroidism during treatment; 3) euthyroid with negative thyroliberin test (subclinical hyperthyroidism); 4) euthyroid with low thyroliberin test; 5) euthyroid with normal thyroliberin test; 6) euthyroid with high thyrotropin level (subclinical hypothyroidism); and 7) primary hypothyroidism. Patients in groups 2-6 were undergoing treatment with mercazole and propylthiouracil. The new immunoluminometric assay (ILMA) BeriLux kit was shown to have a remarkably improved analytical and clinical sensitivity. The minimal detectable level of thyrotropin in the assay was 0.006 mU/l. The precision was 2.8% and 6.1% at 0.093 +/- 0.003 mU/l and 0.028 +/- 0.002 mU/l, respectively, whereas the precision of the other methods was above 17.2% and 59.4% respectively. Seven patients from the untreated hyperthyroid group were given 500 micrograms thyroliberin i.v. (the thyroliberin test). The thyrotropin pattern before and after thyroliberin administration was always less than 0.006 mU/l with the BeriLux kit, whereas the other methods showed random fluctuations indicating their low accuracy at this concentration. Using the BeriLux kit, 7 of the 16 overt hyperthyroid patients undergoing treatment showed a measurable thyrotropin level below 0.01 mU/l but a negative thyroliberin test.(ABSTRACT TRUNCATED AT 250 WORDS)
Hashimoto
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T
Department of Laboratory Medicine, Kanazawa University School of Medicine, Ishikawa, Japan.
Matsubara
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Nishibu
M
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Kawai
K
K
D000328:Adult; D005069:Evaluation Studies as Topic; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy; D006801:Humans; D007118:Immunoassay; D007124:Immunoenzyme Techniques; D015592:Immunoradiometric Assay; D008163:Luminescent Measurements; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D008875:Middle Aged; D011441:Propylthiouracil / Q000627:therapeutic use; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D008713:Methimazole; D013973:Thyrotropin-Releasing Hormone; D011441:Propylthiouracil; D013972:Thyrotropin; D013974:Thyroxine