DEVELOPMENT OF A TWO–STEP IMMUNORADIOMETRIC ASSAY FOR  SERUM THYROGLOBULIN USING A COMBINATION OF POLYCLONAL AND MONOCLONAL ANTIBODIES

Chandrakala Gholve; J. Kumarasamy; Archana Damle; Savita Kulkarni; M G R. Rajan

Volume : VI, Issue : III, March - 2016

DEVELOPMENT OF A TWO–STEP IMMUNORADIOMETRIC ASSAY FOR SERUM THYROGLOBULIN USING A COMBINATION OF POLYCLONAL AND MONOCLONAL ANTIBODIES

Chandrakala Gholve, J. Kumarasamy, Archana Damle, Savita Kulkarni, M G R. Rajan

Abstract :

Thyroglobulin (Tg) is used as a tumor marker in the follow–up cases of differentiated thyroid carcinoma (DTC) patients. A sensitive immunoradiometric assay (IRMA) for serum Tg estimation was developed at our Centre with analytical and functional sensitivities of 0.2 ng/ml and 1.0 ng/ml respectively. The assay used anti–Tg rabbit polyclonal antibody as capture antibody and 125I labeled monoclonal antibody as detector antibody. The assay was optimized for various reaction conditions with a working range of 1.0–800 ng/ml. The mean intra– and inter–assay coefficient of variation (CV) for QC samples was 6.95% and 8.85% respectively. Stability of the antibody coated tubes was up to 12 months. Good correlation was obtained when compared with commercial DiaSorin Tg IRMA kit (r=0.93, n=249, p<0.001)). All the samples included for the study were anti–Tg autoantibody (TgAb) negative as they are known to interfere in Tg assays.