Diagnostic value of serum TSI levels in Graves' disease and direct comparison of diagnostic performance with TRAb: A systematic review and meta-analysis.

This study aimed to systematically assess the diagnostic value of thyroid-stimulating immunoglobulin on the Siemens Immulite platform (the TSI assay) and to conduct a direct comparison with thyrotropin receptor antibodies on the Roche cobas platform (the TRAb assay) for the diagnosis of Graves' disease (GD). We performed systematic literature searches across multiple databases. Following strict screening, we identified 20 eligible clinical studies that evaluated the diagnostic value of the TSI assay, either alone or in comparison with the TRAb assay. Using random-effects models, we calculated pooled estimates of sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Diagnostic accuracy was further evaluated through summary receiver operating characteristic curve analysis. The findings revealed that the TSI assay demonstrated excellent diagnostic accuracy, with pooled SEN of 0.933 (95 % CI: 0.924 - 0.941), SPE of 0.961 (95 % CI: 0.956 - 0.964), PLR of 24.078 (95 % CI: 16.727 - 34.659), NLR of 0.036 (95 % CI: 0.020 - 0.066), and DOR of 778.29 (95 % CI: 343.45 - 1763.67), supported by an area under the curve (AUC) of 0.9919. In direct comparison to the TRAb assay, the TSI assay showed slightly better SEN (0.967 vs. 0.889), DOR (1310.03 vs. 692.73), and NLR (0.023 vs. 0.046), comparable SPE (0.964 vs. 0.959) and PLR (29.954 vs. 30.066), and higher AUC (0.9963 vs. 0.9899). These results conclusively demonstrate that the TSI assay shows high sensitivity and specificity in the diagnosis of GD, exceeding or at least comparable to TRAb, making it a valuable tool for clinical diagnosis.