Investigations of thyroid diseases--an update on diagnostic methods

Iodine deficiency disorders (IDD) are an important public health problem in India. It requires further refinement and improvements in thyroid disease diagnosis, especially in the early diagnosis of thyroid malfunctioning and risk assessment of autonomously functioning thyroid tissue. Scintigraphy with technetium-99m pertechnetate under exogenous or endogenous thyroid stimulating hormone (TSH) suppression provides the best results. There has been significant improvement in methodology in various laboratory investigations that have resulted from the application of newer luminescent techniques and gene technology in various thyroid function tests. TSH measurement especially by using second or third generation assays has ensured diagnostic accuracy and thyrotropin releasing hormone (TRH) test now almost always unnecessary. Determination of glycosaminoglycans in urine may become a helpful tool in the follow up of endocrine ophthalmopathy. The differentiation of blocking and stimulating TSH receptor antibodies is relevant when discrepant results are obtained with respect to thyroid function. Some newer imaging agents have been used in thyroid disease scintigraphy such as octreotide or in thyroid diseases diagnosis such as fluorodeoxyglucose. Both improve the detectability of thyroid cancer metastasis especially if radioiodine scan is negative.