Predictive value of serum thyroglobulin in treated patients with differentiated thyroid carcinoma.

An in-house radioimmuno assay for serum thyroglobulin was developed in our laboratory and compared its relative sensitivity with that of whole body scan in the detection of residual tumour or metastases and evaluated the predictive value of serum thyroglobulin in the clinical course of the disease. Ninety six patients after thyroidectomy were followed up for a maximum period of five years in this study.The sensitivity and specificity of serum thyroglobulin were found to be close to that of whole body scan (85% and 94% respectively). According to this study, a serum thyroglobulin >40 ng/ml can differentiate between patients with metastases and those in remission. Serum thyroglobulin can replace whole body scan during the subsequent follow-up if the patient had concordant whole body scan and serum thyroglobulin during initial assessment.