The hTSH Measurement by Solid-Phase Fluoro Immunoassay and Using FITC as Probe

Abstract

Different fluoroimmunoassay methods for thyrotropin (hTSH) measurement have been discussed previously. We describe here fluoroimmunoassay method based on solid-phase system and using antigen-binding FITC to measure hTSH.The monoclonal antibody immobilized on polystyrene tubes were used for competitive binding of serum sample hTSH and F-TSH. The fluorescein-labeled TSH (F-TSH) were prepared by overnight incubation of fluorescein isothiocyanate
(FITC) and commercial pure TSH, followed by gel filtration(G-25) purification to obtain pure F-TSH.The constracted standard curve (from F-TSH) was linear from 0.05 to 15 mIU/L. The interassay coefficient of variation was 7.3% ,11.2% , 6.3% , at 0.015 , 0.5 and 15 mIU/L TSH, and intraassay CV was 10.2% , 6.0% and 7.7% at mentioned TSH concentration, respectively. A good correlation was found with RIA ( y = .097±0.046 , r = 0.91 , P< 0.005 , n = 43).Our approach assay method has advantages of suitable sensitivity that alow the identification of primary hyperthyroidism,independent of serum effect, fast, technically simple and low cost , which is ideally suited to use in routine and normal clinical laboratories.