Indigenous IRMA Kit for routine estimation of serum thyroglobulin in thyroid cancer patients: Radiation Medicine Centre, BARC completing a decade of accomplishment

Radiation Medicine Centre (RMC) is one of the largest referral bases in India for the management of patients with various thyroid disorders including differentiated thyroid cancer (DTC). Constant efforts are being put in both in-vivo and in-vitro diagnostics for better care and management of the patients. RMC is a pioneer in Nuclear Medicine and due to its established infrastructure, various radioisotopic assays for thyroid analytes [Total T4, Free T4, anti-thyroid peroxidase autoantibody (TPOAb), serum thyroglobulin (Tg) and anti-Tg autoantibody (TgAb)] have been developed and validated here and some of them also found its applications for routine in-vitro patient services. Serum Tg is one of these in-house developed assays which was first developed in RMC and is still being used as a 'tumor marker' in the monitoring of thyroid cancer patients for almost 40 years. Thyroid cancer is the most common type of endocrine malignancy. About 90% of thyroid neoplasms are differentiated thyroid cancers with low malignant potential and a very good prognosis. Serum Tg measurement is clinically useful for the postoperative monitoring of patients diagnosed with DTC with detectable and/or increasing Tg concentration indicating possible recurrent or persisting disease. To cater to the increasing patient load we switched over to imported commercial IRMA kits (a window period). The commercial kits being highly expensive prompted us to standardize a two-step solid-phase IRMA using antibodies coupled to Magnetic particles (MP) and polystyrene-coated tubes (CT) as different solid-phases. Among the two developed IRMA formats, the CT-IRMA had better possibilities to be implemented for routine use in terms of sensitivity, precision and automation with a significant reduction in the TAT (14 h) thereby making the reporting time rapid