The Ratio of Thyroglobulin in Wash-Out Fluid From Fine-Needle Aspiration to Serum Thyroglobulin Level in the Evaluation of Metastatic Cervical Lymph Nodes in Patients With Papillary Thyroid Cancer

Abstract Fine needle aspiration with cytology analysis and thyroglobulin level of the aspirated biopsy (FNAB-Tg), is an important tool to assess metastasis cervical lymph nodes (CLN) in patients papillary thyroid cancer (PTC) who have suspicious node features on ultrasound. Despite great diagnostic accuracy FNAB-Tg, studies failed define best cutoff value for FNAB-Tg. In our study, we describe a novel way performing Tg washout process it locally at laboratory (tertiary care center). We used FNAB-Tg serum (FNAB-Tg/ serum) ratio help overcome heterogeneity both values assays detect level. conducted retrospective 22 PTC or suspected patients, All underwent fine-needle aspiration, from CLNs. was obtained all subjects using following method: Blood samples are drawn patient’s peripheral vein placed two yellow top tubes (3 ml blood each tube). 1 normal saline (NS) added Tube # (Tg Serum The aspirate via US-guided FNA. It washed NS tube #2 (FNAB-Tg Both sent local assay. FNAB-Tg/ calculated. If FNAB-Tg/Serum-Tg ratio>3, this suggestive CNL metastasis. compared results histopathology reports after neck dissection.59% (13/22) had consistent metastatic PTC. 12 out these 13 FNAB-Tg/serum >3 one TG < 3, though 4474 ng/ml 2444 ng/ml. Metastatic CLNs confirmed pathology report total thyroidectomy dissection. Six studied (27%) negative > 3. 5 dissection institute One patient elected surgery his home country not available time. Three (14%) <3. 2 them final concordant results. method differences measure FNAB. An FNAB–Tg/serum more accurate than detecting (PTC). 27% CLN would been missed if FNAB alone. This will optimize surgical approach before initial recurrence.