Diagnostic efficiency of thyroglobulin in lymph node fine-needle aspiration washout: A systematic review and meta-analysis

Context Cervical lymph node metastases are common in papillary thyroid carcinoma (PTC), causing recurrence and poor regional control, highlighting the need for accurate diagnostics. Although fine-needle aspiration with thyroglobulin washout (FNA-Tg) shows promise, its diagnostic performance and association with serum biomarkers across settings remain unclear. Objective To assess the diagnostic performance of FNA-Tg for cervical lymph node metastases in PTC and its correlation with serum Tg (s-Tg) and serum Tg antibody (s-Tg-Ab) levels. Data Sources PubMed, Embase, Web of Science, Scopus, Cochrane Library, and Ovid Medline were searched for relevant studies. Study Selection Studies enrolling PTC patients with cervical lymphadenopathy who underwent FNA-Tg pre- or post-thyroidectomy were included. Studies involving non-PTC populations or lacking sufficient data for 2×2 diagnostic table construction were excluded. Data Extraction Data were independently extracted by three researchers, and study quality was assessed by QUADAS-2 tool. Data Synthesis FNA-Tg showed pooled sensitivity of 0.94 (95% CI, 0.91–0.96), specificity of 0.92 (95% CI, 0.88–0.94), and diagnostic odds ratio (DOR) of 174.20 (95% CI, 87.05–348.61), with an area under curve (AUC) of 0.98 (95% CI, 0.96–0.99). Post-thyroidectomy, sensitivity increased to 0.96 (95% CI, 0.94–0.98), specificity to 0.93 (95% CI, 0.86–0.96), and DOR to 305.87 (95% CI, 127.99–730.93), with an AUC of 0.98 (95% CI, 0.97–0.99). In the Thyroid (-) group, sensitivity was 0.96 (95% CI, 0.93–0.97), specificity 0.93 (95% CI, 0.87–0.97), and DOR 300.27 (95% CI, 118.47–761.05), with an AUC of 0.98 (95% CI, 0.97–0.99). Likelihood ratio scattergrams and Fagan plots supported its discriminatory ability. FNA-Tg correlated weakly with s-Tg but not with s-Tg-Ab. Conclusion FNA-Tg showed high diagnostic accuracy, especially after thyroidectomy, with minimal s-Tg-Ab interference, supporting its role in PTC surveillance.