Immunoradiometric assay for the in-vitro determination of thyroid stimulating hormone in human serum and plasma using solid phase anti-TSH cellulose particles

Abstract

Development, optimization and validation of immunoradiometric assay (IRMA) using solid phase-cellulose particles for the measurement of TSH in human serum or plasma are described. The preparation of 125I anti-TSH monoclonal antibody (MoAb) was carried out by two different methods (Chloramine-T and Iodogen). It was found that Ch-T method gave approximately the same results as the iodogen method. The activation of cellulose particles using 1,1-carbonyl diimidazole (CDI) and coupling of these solid phase particles with sheep anti-TSH were carried out. Optimization and validation of the assay were undertaken. The reproducibility as measured by the intra- and inter-assay variations is acceptable. The recovery and dilution tests indicated accurate calibration and appropriate matrix. No significant position effect was recognized. The different modes of sampling tested did not affect significantly the results of the present study. The present technique agreed well with the currently used commercial kit (DPC, IRMA). The cellulose particles of the present system for estimation of TSH retain their characteristics during storage for 6 months at 4 °C. In conclusion, this technique proved to be sensitive, specific, precise and accurate for routine laboratory use.