Comparative performance of ELISA and dot blot assay for TSH-receptor antibody detection in Graves' disease

Background Graves' disease (GD) is an autoimmune disease, and it accounts for major cases of hyperthyroidism. Antibody against thyroid-stimulating hormone receptor/TSHR (TRAb) is responsible for hyperthyroidism and is considered as a diagnostic marker for GD. Therefore, we developed a recombinant protein of human TSHR-169 (hTSHR-169), which was specifically recognized TRAb in the serum of GD patients and then compare the diagnostic performance between ELISA and dot blot of TRAb tests for their ability to diagnose GD. Methods 20 GD patients and 20 healthy individuals from the Indonesian population were enrolled. TRAb concentration and density were quantified. Comparative analysis was performed using receiver-operating curve (ROC) analysis. Results For dot blot assay, the minimum concentration to detect TRAb requiring 100 ng of antigen with antiserum diluted at 1:60. For diagnosing GD, the ELISA yielded a higher AUC compared with the dot blot assay (0.95 and 0.85, respectively). Using the recommended cutoff values, the efficiency of both assays was examined by comparing the specificity and sensitivity of the assays to the clinical diagnosis. The ELISA showed 80% and 95%, while the dot blot assay showed 70% and 95% sensitivity and specificity, respectively. Conclusion Although the dot blot assay exhibited lower performance than the ELISA method, the dot blot assay is a simple and rapid diagnostic assay that is suitable for diagnosing GD in rural areas, in which healthcare facilities sometimes are not accessible.