PROSPECTIVE STUDY TO COMPARE RESULTS OF THYROID FUNCTION TESTS OF FLUORESCENT IMMUNOASSAY(FIA) AND ENZYME LINKED RADIOIMMUNOASSAY(ELISA) WITH GOLD STANDARD CHEMILUMINISCENCE TEST(CLIA) TEST IN A TERTIARY CARE HOSPITAL

Background: Thyroid function test is widely used parameter to diagnose thyroid illness. Since introduction of radioimmunoassay method, several improvements are made in this technique. so it is important to define best sensitive assay with diagnostic accuracy to perform TFT in small laboratories . Therefore we performed analytical evaluation of results of serum total T3, total T4, TSH level by ELISA , FIA with gold standard CLIA method. Material & Methods: In this study total of 40 participants were enrolled. Subjects were chosen randomly either attending OPD & IPD . Serum total T3, total T4, TSH levels were measured in subjects by all three method FIA, ELISA and CLIA. Results of FIA and ELISA test were compared with gold standard CLIA test in terms of sensitivity, specificity, positive predictive value and negative predictive value & diagnostic accuracy. Results: Sensitivity of serum total T3, totalT4, TSH by ELISA is 75% FIA 88%, specificity of serum total T3,T4, TSH by ELISA is 67% and FIA 75%, PPV of all three parameter by ELISA is 60% & FIA 70%, NPV by ELISA is 80% & FIA is 90% Conclusion: Results of serum total T3,serum total T4 and serum TSH by FIA method is comparable with results of CLIA method in term of sensitivity, specificity, positive predictive value and negative predictive value & can be used as reliable &efficient diagnostic test for measurement of serum Total T3, serum Total T4, serum TSH in small laboratories.