Chemiluminescent third-generation assay (Amerlite TSH-30) of thyroid-stimulating hormone in serum or plasma assessed.
We assessed the laboratory performance and clinical utility of a new commercial third-generation assay of thyroid-stimulating hormone (TSH), Amerlite TSH-30. The interassay CV was 6% at TSH concentrations of approximately 0.08 mIU/L, and the analytical and functional detection limits of the assay were 0.005 and 0.0125 mIU/L, respectively. Although the assay recovered approximately 96% of TSH International Reference Preparation (TSH-IRP) 80/558 added to serum samples, the endogenous TSH concentrations in basal samples were significantly lower than those found by using two other TSH assays; bias data obtained from thyroliberin stimulation tests suggested that the negative bias found with TSH-30 may be due to the heterogeneity of TSH in basal samples. TSH-30 completely discriminated hyperthyroid and hypothyroid patients from euthyroid ambulatory patients but also detected TSH (> 0.0125 mIU/L) in 3 of 46 untreated hyperthyroid patients. Compared with two second-generation assays, TSH-30 better discriminated between patients with subnormal TSH due to hyperthyroidism, thyroxine overreplacement, and nonthyroidal illness but there was still significant overlap between results for these groups.
Wilkinson
E
E
University Department of Clinical Biochemistry, Royal Infirmary, Edinburgh, Scotland, UK.
Rae
P W
PW
Thomson
K J
KJ
Toft
A D
AD
Spencer
C A
CA
Beckett
G J
GJ
D015982:Bias; D006111:Graves Disease / Q000097:blood; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D007075:Immunoglobulin M / Q000097:blood; D008163:Luminescent Measurements; D011786:Quality Control; D012016:Reference Values; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000627:therapeutic use
D007075:Immunoglobulin M; D013972:Thyrotropin; D013974:Thyroxine