Comparison of Thyroid Function Tests by RIA / IRMA Based Commercial Kit and in House Method in Hypothyroid Patients

The diagnosis of hypothyroidism is based on the combination of clinical presentation and laboratory tests. The current study focuses on the strategy for the differential diagnosis of hypothyroidism and a comparison of thyroid function tests (TFTs) by commercial kit based RIA / IRMA (radioimmunoassay / immunoradiometric assay) procedures with those by in – house method. The study encompasses 75 hypothyroid patients whose clinical history were recorded and TFTs were performed on their serum samples by commercial kit based RIA / IRMA. Moreover, 40 samples were assayed again for TFTs by in – house RIA / IRMA procedures to check whether the results by both methods were comparable. It has been found that in most cases, hypothyroidism is a clinical diagnosis and estimation of TFTs is required for its confirmation but to reach the differential diagnosis of hypothyroidism, additional relevant investigations are required. Furthermore, when TFTs results by commercial kit based RIA / IRMA were compared with those by in – house RIA / IRMA procedures, no statistically significant difference was found between the two methods. This implies that in – house RIA / IRMA procedures may be applied in place of commercial kit based methods to perform TFTs provided the criteria for quality control are fulfilled.