Fine-needle Aspiration Washout Fluid Research Articles

Detection of thyroglobulin for diagnosis of metastatic lateral cervical lymph nodes in papillary thyroid carcinoma: accuracy and application in clinical practice.

Accurate assessment of lateral cervical lymph node metastasis (LLNM) involvement is important for treating papillary thyroid carcinoma (PTC). Thyroglobulin is associated with LLNM, but there may be differences in the diagnostic value of serum thyroglobulin (sTg) and fine needle aspiration washout fluid thyroglobulin (FNA-Tg). Herein, we investigated the optimal cutoff value (OCV) of sTg and FNA-Tg and their diagnostic performance. We enrolled 116 PTC patients who underwent radical resection of thyroid carcinoma with lateral cervical lymph node dissection at the Affiliated Hospital of Zunyi Medical University from June 2018 to July 2022. We used the receiver operating characteristic (ROC) curve analysis to determine the OCV for sTg and FNA-Tg to diagnose LLNM in PTC patients. We also evaluated the performance of FNA-Tg, sTg, fine needle aspiration cytology (FNAC), and their combinations for diagnosis. Pathological results were the gold standard. We performed 125 lymph node dissections, 106 had metastasis, and 19 did not. The OCV for sTg was 17.31 ng/mL [area under the curve (AUC) =0.760, sensitivity =78.30%, specificity =73.68%, and accuracy =77.60%]. Meanwhile, the OCV for FNA-Tg was 4.565 ng/mL (AUC =0.948, sensitivity =89.62%, specificity =100%, and accuracy =91.20%). The combination of FNAC and FNA-Tg presented the greatest diagnostic performance for LLNM detection in PTC patients. Moreover, serum antithyroglobulin antibody (TgAb) was not correlated with sTg or FNA-Tg levels. The cutoff value for the diagnosis of LLNM in PTC are sTg >17.31 ng/mL or FNA-Tg >4.565 ng/mL. The combination method of FNA-Tg and FNAC is the most optimal choice for the diagnosis of LLNM and is highly recommended for further clinical application.

Evaluation of calcitonin measurement in fine needle aspirates in the diagnosis of primary and metastatic medullary thyroid carcinoma

Serum CT represents the tumoral marker of medullary thyroid carcinoma (MTC), and is a main diagnostic tool and follow-up after treatment. Nevertheless, calcitonin levels can be elevated in a number of other situations and does not always distinguish MTC from other clinical circumstances, particularly when elevation remains moderate. Fine needle aspiration biopsy is a widely used examination for the investigation of thyroid nodules and lymph nodes, but its sensitivity for the diagnosis of MTC remains low ranging from 45% to 63%. Calcitonin measurement in fine needle aspiration wash out fluid has been reported as reliable, and is recommended by the experts of American Thyroid Association (ATA) in their 2015 consensus for the management of MTC even if its diagnostic is not standardized yet. Material and methods: Twenty patients with 45 lesions (thyroid nodule and lymph node) were included in this study; calcitonin was performed in each of them, the puncture needles were washed with 1ml of saline solution to obtain to measure Calcitonin in fine needle aspiration washout fluid. Results: After surgery 32 MTC were diagnosed on histology. Receiver operating curve (ROC curve) indicated CT in fine needle aspiration >22.99pg/ml as more accurate cut off value with a sensitivity and specificity of 96.87% and 100%. Calcitonin ratio was evaluated too, the cut off value being>0.64 with a sensitivity of 62.5% and specificity of 100%. Conclusion: Calcitonin in fine needle aspiration wash out fluid constitutes an excellent diagnostic tool of MTC with the use of 22.99pg/ml threshold.

An old friend, a new insight: Calcitonin measurement in serum and aspiration needle washout fluids significantly increases the early and accurate detection of medullary thyroid cancer.

The sensitivity of cytological (CY) evaluation after fine-needle aspiration (FNA) for detecting medullary thyroid carcinoma (MTC) is a subject of controversy. The routine use of serum calcitonin (CT) in patients with thyroid nodules is not universally adopted. The authors conducted CT screening of FNA washout fluid (FNA-CT) to address the diagnostic challenges. The objective was to assess the contributions of serum CT, FNA cytology (FNA-CY), and FNA-CT to the diagnosis. Between February 2019 and June 2022 (group 1), the authors prospectively screened the CT of patients with thyroid nodules. Both FNA-CY and FNA-CT were performed for patients with persistently elevated CT values. The sensitivity of FNA-CY, serum CT, and FNA-CT for accurate diagnosis was evaluated. Additionally, the authors retrospectively examined data from patients with thyroid nodules before CT screening (2008-2019) (group 2). They compared the characteristics of MTC patients in groups 1 and 2. MTC was identified in 30 patients (0.25%) in group 1 and 19 (0.07%) in group 2. A FNA-CT cutoff value of 4085.5pg/mL detected MTC with a sensitivity of 96.8%, and a serum CT cutoff value of 28.3pg/mL detected MTC with a sensitivity of 86.7%. In contrast, FNA-CY detected MTC with a sensitivity of 42.4%. In group 1, 18 patients (60%) with MTC were diagnosed with microcarcinoma, whereas only two patients (10.5%) in group 2 had microcarcinoma. This study detected MTC earlier by routinely measuring serum CT in all patients with nodular thyroid disease and performing FNA-CT in those with elevated values. FNA-CT and serum CT sensitivities were significantly higher than those of FNA-CY. This study revealed different FNA-CT cutoff values compared to other studies, emphasizing the need for determining clinic-specific cutoff values.

Diagnostic value and cost-effectiveness of FNA-CT versus FNAC for medullary thyroid carcinoma.

To evaluate the diagnostic performance and cost-effectiveness of calcitonin assays in fine-needle aspiration washout fluid (FNA-CT) compared to fine-needle aspiration cytology (FNAC) for medullary thyroid carcinoma (MTC). A total of 27,404 patients from three medical centres between January 2020 and May 2022 were screened for serum calcitonin (sCT). Of whom, 223 patients met endpoints and were enroled for analyses. Based on sCT levels, patients were divided into two groups (group 1: 10 pg/ml< sCT ≤100 pg/ml and group 2: sCT > 100 pg/ml). The diagnostic performance and cost-effectiveness of FNA-CT and FNAC were compared. Most patients (N = 25,228; 92.1%) with thyroid nodules had normal sCT levels. In group 1, 24 and 167 nodules were diagnosed as MTC and non-MTC lesions, respectively. FNA-CT showed better performance in diagnosing MTC than FNAC in terms of sensitivity (100.0% vs. 58.3%), negative predictive value (100.0% vs. 94.3%), and overall accuracy (100.0% vs. 94.7%). In group 2, 67 and 7 nodules were diagnosed as MTC and non-MTC lesions, respectively. The diagnostic performance of FNA-CT was superior to FNAC in terms of sensitivity (100.0% vs. 64.2%), negative predictive value (100.0% vs.22.6%), and overall accuracy (100.0% vs. 67.6%). Furthermore, analysis from the decision tree model showed that FNA-CT was a cost-effective tool for diagnosing MTC lesions. FNA-CT can serve as an auxiliary and cost-effective approach for patients with indeterminate sCT levels to detect occult MTC lesions. FNA-CT can be recommended for patients with sCT >100 pg/ml to overcome the high false-negative rate of FNAC.

The Role of Thyroglobulin in Preoperative and Postoperative Evaluation of Patients With Differentiated Thyroid Cancer.

Thyroglobulin (Tg) is secreted by thyroid follicular cells and stored in the thyroid follicular lumen as a component of thyroid hormone. It is known that both benign and well-differentiated malignant thyroid tissue can secrete Tg. In recent years, growing lines of evidence have shown that Tg plays an important role in the diagnosis and metastasis of preoperative differentiated thyroid carcinoma (DTC). The levels of Tg, whether in the serum or in a fine-needle aspiration washout fluid, are usually viewed as an excellent indicator in the monitoring of postoperative DTC, including the guidance and evaluation of radioactive iodine ablation. Nevertheless, some factors limit the application of Tg, such as the method used to measure Tg and the presence of Tg antibodies. This review aimed to summarize the role of Tg in the preoperative and postoperative evaluation of patients with DTC, and the factors influencing Tg. This review could provide a reference for a more accurate application of Tg in patients with DTC.

Measurement of thyroglobulin level in lateral neck lymph node fine needle aspiration washout fluid in papillary thyroid cancer.

Thyroglobulin (Tg) level of fine needle aspiration (FNA) washout fluid (FNA-Tg) is useful to detect cervical lymph node (LN) metastasis in patients with papillary thyroid cancer (PTC). The objective of this study was to determine appropriate cutoff values of serum Tg (S-Tg) and FNA-Tg levels for diagnosis of lateral neck LN metastasis and investigate their diagnostic performance. A total of 169 patients with PTC who underwent modified radical neck dissection (mRND) were retrospectively reviewed at Seoul St. Mary's Hospital (Seoul, Korea) from December 2011 to September 2019. Diagnostic performance of FNA-Tg, Tg ratio (FNA-Tg level/S-Tg level), and FNA-Tg combined with Tg ratio was evaluated by correlation with FNA cytology results. FNA-Tg level ≥20 ng/mL exhibited 86.6% sensitivity, 66.7% specificity, and 81.7% accuracy. Tg ratio ≥3 exhibited lower sensitivity but higher specificity (82.7% and 73.8%, respectively) than FNA-Tg level ≥20 ng/mL. FNA-Tg level ≥20 ng/mL combined with Tg ratio ≥3 had 81.9% sensitivity, 80.5% accuracy, and an integrated area under the curve (iAUC) of 0.790. Measurement of FNA-Tg level increases preoperative diagnostic accuracy for the detection of metastatic LNs in patients with PTC. Diagnostic accuracy is higher using a 20 ng/mL FNA-Tg cutoff level. Tg ratio is also valuable and FNA-Tg combined with Tg ratio shows promise.

Value of Pyruvate Carboxylase in Thyroid Fine-Needle Aspiration Wash-Out Fluid for Predicting Papillary Thyroid Cancer Lymph Node Metastasis.

The incidence of papillary thyroid carcinoma (PTC) is increasing. Lymph node metastatic status of PTC is a major factor for decision marking of surgery and surgical extend, however, no reliable tool exists for prediction of PTC nodal metastasis, for example, ultrasound cannot qualitatively diagnose and effectively detect central lymph node metastasis (CLNM). Therefore, the development of a new diagnostic biomarker is crucial for CLNM. Metabolic dysregulation is an important factor associated with malignancy and metastasis of tumors. Pyruvate carboxylase (PC) is a major anaplerotic enzyme that catalyzes the carboxylation of pyruvate to form oxaloacetate, which has been suggested to be involved in the tumorigenesis of several cancers, including PTC. This study aimed to explore the role of PC expression in thyroid fine-needle aspiration (FNA) wash-out fluid for predicting CLNM in PTC, and to explore how PC is involved in PTC development. The expression levels of PC in PTC tissues and normal thyroid tissues were first compared based on bioinformatics analysis of public databases, including the Gene Expression Profiling (GEPIA), Oncomine and Gene Expression Omnibus (GEO) databases. Then, the PC mRNA and protein expression levels were measured by RT-PCR and Immunohistochemistry (IHC) in surgical tissues from a total of 42 patients with surgically confirmed PTC, and compared in patients with and without CLNM. Further, to assess PC expression in diagnostic biopsies, a total of 71 thyroid nodule patients with ultrasound-guided FNA wash-out fluid samples and cytological diagnosis were prospectively enrolled in the study. Then, we analyzed the mechanism of PC-mediated PTC progression in vitro. This study showed that PC expression was higher in PTC tissues and thyroid FNA wash-out fluid samples from patients with CLNM than those from patients without CLNM, and that PC-induced PTC metastasis may occur through the TGF-β/Smad-regulated epithelial–mesenchymal transition (EMT) pathway.

Mildly Elevated Basal Calcitonin Level in Patients With Thyroid Goiter: Using the Calcitonin Measurement in Fine-Needle Aspirate Washout Fluid of the Healthy Lobe to Define Medullary Thyroid Cancer and Reactive C-Cell Hyperplasia

Abstract Background: Mildly elevated basal calcitonin level (bCT), that suggests a bCT increase up to 100 pg/ml, may testify either medullary thyroid carcinoma (MTC) or reactive thyroid C-cell hyperplasia (CCH). The latter is observed under many conditions such as hypercalcemia, hypergastrinemia, thyroiditis, neuroendocrine tumors (NET), renal end-stage kidney disease, obesity, and smoking. The research is aimed at analyzing the clinical significance of the calcitonin measurement in the fine needle aspiration washout fluid sample (FNA-CT) for screening certain patients with nodular thyroidopathy and elevated bCT. Patients and Methods: 70 patients with mildly elevated bCT (for women 6-100 pg/ml, for men 19-100 pg/ml) underwent ultrasound-guided FNA-CT measurement of the thyroid nodules and healthy lobe tissue. After obtaining a FNA-CT specimen, the needle was washed with 0.5 ml of saline solution. The calcitonin (CT) was measured by ECLIA (LIAISON XL). Results: There were 51 females and 19 males, with a mean age of 46.8 ± 14.4 years (range 16-81). The mean value of bCT was 23.3 ± 19 pg/ml (range: 7-86.5). According to ultrasound, 66 patients (95%) presented with thyroid nodules, in 4 cases previously identified nodes were not confirmed. The mean lesion size was 10.8 ± 4.9 mm (range: 4-26). Thyroid nodules were evaluated by FNA biopsy which revealed according to the Bethesda system category I in 6 cases, II - 44, III - 2, IV - 4, V - 6, and VI - 1. Analyzing FNA-CT results we identified 13 cases (18%) with MTC with low CT level of healthy lobe tissue (1-89.6 pg/ml) and high CT level of the lesion (&amp;gt;2000 pg/ml), which was confirmed by final histological examination. Low CT level from both healthy lobe and the nodule (&amp;lt;20 pg/ml) was observed in 10 cases, we carried out the measurement of stimulated CT to exclude the extrathyroidal CT production, which was confirmed in 1 case. All 4 patients with no nodules possessed significantly higher T-rates (1650-2000 pg/ml). The remaining 43 cases (61%) had an increased CT-level of healthy tissue (&amp;gt;2000 pg/ml) with a lower level from the lesion. Among these patients, the probable predisposing CCH factors were obesity - 8 cases, thyroiditis - 12, NET - 3, hypercalcemia - 3, renal kidney disease - 1, and smoking - 3. These 54 patients were kept under dynamic control. The observation period for patients - 1 year. 4 patients underwent surgical treatment, subsequently, histological examination revealed papillary thyroid cancer, follicular adenoma, colloid goiter against CCH, and CT-producing NET. Conclusion: The measurement of FNA-CT of the healthy lobe tissue may be useful to differentiate MTC and CCH, but requires new data in a major cohort of patients. The disadvantage of this study is the impossibility of CCH histological verification in the follow-up group.

Early diagnosis of medullary thyroid cancer in case of low serum calcitonin: Role of calcitonin measurement in fine-needle aspiration washout fluid

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Serum thyroglobulin elevation after needle aspiration of the lymph nodes: the predictive value for detecting metastasis in papillary thyroid cancer patients – a pilot study

Ultrasonography (USG)-guided fine needle aspiration (FNA) is widely used for diagnosis of lymph node (LN) metastasis in papillary thyroid cancer (PTC). However, FNA cytology sometimes shows inconclusive results. Recently, the measurement of thyroglobulin (Tg) in FNA washout fluid (aspirate-Tg) has been widely adopted, but there are some difficulties in the preparation of the sample and standardization of the procedure. Here, we examined serum Tg after FNA as a new predictive marker for LN metastasis of PTC. We performed USG-guided FNA cytology and examined aspirate-Tg in PTC patients showing suspicious metastatic LNs during follow-up. We measured baseline serum thyroid stimulating hormone (TSH), Tg, and Tg antibody levels before FNA, and serum Tg level within an hour after FNA. We defined aspirate-Tg level above 0.9 ng/mL as positive, and a 30% increase in serum Tg level after FNA compared to the baseline as elevation of serum Tg. Twenty-two patients were included in our study. Nine patients (40.9%) showed elevation of Tg level after FNA, and the mean value of Tg elevation was 24.8 ± 48.0 ng/mL. Among these 9 patients, 8 were diagnosed with PTC and 1 patient showed cellular atypia on cytopathology. All these patients showed positive aspirate-Tg. Thirteen patients (59.1%) did not show elevation of Tg level after FNA. Among these patients, 2 had PTC, 2 had cellular atypia, and 9 yielded negative results for malignancy on cytopathology. Elevation of serum Tg level after FNA might have a diagnostic role for predicting LN metastasis of PTC.

Thyroglobulin measurement in fine-needle aspiration washout fluid for detection of differentiated thyroid cancer lymph nodes metastases

Objective: To investigate the feasibiity of detecting lymph node metastasis in differentiated thyroid cancer patients by thyroglobin（Tg）measurement in fine-needle aspiration washout fluid. Method: Forty-seven differentiated thyroid cancer patients with cervical lymph node metastasis were included in this study. Fine-needle aspirations were performed on lymph nodes which were surgically resected for measurement of Tg in washout fluid. Diagnostic sensitivity, specificity and accuracy were evaluated according to three predetermined Tg threshold values: FNA-Tg/serum Tg＞1, 10 ng/ml and 100 ng/ml. Result: The meadian value of FNA-Tg in metastatic lymph node (n=46) was 5 177 ng/ml (1.79-408 300 ng/ml)，while lymph node without metastasis (n=11) showed a meadian level of 0.63 ng/ml (0.04-125.4 ng/ml). With the threshold of FNA-Tg level at FNA-Tg/serum Tg＞1, 10 ng/ml and 100 ng/ml respectively, the diagnostic sensitivity was 91.3%, 97.83% and 93.48% respectively,the specificity was 81.82%,63.64% and 90.90% respectively,and the accuracy was 89.47%,91.22% and 92.98% respectively. Conclusion: Thyroglobin measurement in fine-needle aspiration washout fluid is effective to diagnose lymph node metastasis in differentiated thyroid cancer.

A Study on Serum Antithyroglobulin Antibodies Interference in Thyroglobulin Measurement in Fine-Needle Aspiration for Diagnosing Lymph Node Metastasis in Postoperative Patients.

PurposeThyroglobulin measurement in fine-needle aspiration washout fluid (FNA-Tg) is widely used for detection of lymph node metastasis (LNM) in patients with papillary thyroid cancer (PTC). Recent studies suggested that serum anti-thyroglobulin antibodies (TgAbs) could interfere with FNA-Tg. We evaluated whether TgAbs can affect FNA-Tg when diagnosing LNM in postoperative patients with PTC.MethodsFrom November 2006 to June 2011, a total of 239 LNs from 201 patients who underwent bilateral thyroidectomy and radioactive iodine ablation therapy were included. The interactions between FNA-Tgs and serum TgAbs, and diagnostic performances between FNA with additional FNA-Tg and FNA alone according to the presence of serum TgAbs were evaluated using the generalized linear mixed model and the bootstrap method.ResultsFrom 106 (44.4%) malignant and 133 (55.6%) benign LNs, there were 32 (13.4%) LNs with detectable serum TgAb levels and 207 (86.6%) LNs with undetectable serum TgAb levels. In logistic regression analysis, a significant negative interaction was observed between FNA-Tgs and serum TgAbs (p = 0.031). In the absence of serum TgAbs, the diagnostic performances were superior in the FNA with FNA-Tg than in the FNA only. However, in the presence of serum TgAbs, the diagnostic performances of the FNA with FNA-Tg were not significantly different from the FNA only, even with a different cutoff value of FNA-Tg.ConclusionsSerum TgAbs may interfere with FNA-Tg studies and caution is advised while analyzing FNA-Tg for detection of LNM in patients with PTC.

Thyroid diseases cause mismatch between MIBI scan and neck ultrasound in the diagnosis of hyperfunctioning parathyroids: usefulness of FNA–PTH assay

To evaluate the efficacy of the main tools in the diagnostic localization of hyperfunctioning parathyroids (HP) in primary hyperparathyroidism (pHPT) with concomitant thyroid diseases. Forty-three patients with pHPT associated with nodular goiter (NG, n=32) and/or autoimmune thyroid diseases (AITDs, n=11) for a total of 63 neck lesions were considered. Sixteen patients displaying HP (16 lesions), unequivocally localized by sestaMIBI scintigraphy (MIBI) and neck ultrasound (US) (group I), were compared with 27 patients (47 neck lesions) displaying equivocal parathyroid localization (group II). In all cases, neck US, MIBI scan, cytology, and parathyroid hormone assay in fine-needle aspiration washout fluid (FNA-PTH) were performed. All patients finally underwent surgery. According to histological examination, high FNA-PTH values (>103 pg/ml) correctly identified all HP in both groups of patients (100% of sensitivity and specificity). Both MIBI and US correctly identified all HP only in group I patients; in contrast, four patterns of mismatch between these techniques were observed in group II patients, leading to low diagnostic performances of neck US (71.4% sensitivity and 78.9% specificity) and of MIBI scan (35.7% sensitivity and 42.1% specificity). The latter was due to both false-negative (mainly in AITD) and false-positive (mainly in NG) scan images. Coexistent thyroid diseases are responsible for mismatch between MIBI and US images resulting in equivocal HP localization. In these cases, FNA-PTH resulted in the most accurate tool to identify HP. However, although safe, it should be advised only to patients with uncertain HP localization.

Diagnostic Performance of Thyroglobulin Value in Indeterminate Range in Fine Needle Aspiration Washout Fluid from Lymph Nodes of Thyroid Cancer

PurposeThe purpose was to compare the frequency of metastatic and nonmetastatic lymph nodes diagnosed by fine needle aspiration biopsy cytology (FNAC) and thyroglobulin concentration from fine needle aspiration biopsy washout fluid (FNAB-Tg) in an indeterminate range (0.2-100 ng/mL), and to evaluate the most appropriate threshold value of FNAB-Tg in an indeterminate range.Materials and MethodsWe performed ultrasound-guided FNAB and FNAB-Tg in suspicious metastatic cervical lymph nodes of papillary thyroid carcinoma and performed surgery. Ninety-five lymph nodes with indeterminate values of FNAB-Tg ranging from 0.2-100 ng/mL in ninety-two patients were included in this study. The diagnostic performances in multiple Tg levels (0.7, 1.0, 5.0, 10.0, 20.0, 50.0) were evaluated to compare with FNAB cytology using sensitivity, specificity, and accuracy with area under the curve (AUC) analysis.ResultsForty-two were metastatic lymph nodes and fifty three were nonmetastatic lymph nodes. FNAB-Tg ranged from 0.22 to 90.9 ng/mL in metastatic lymph nodes (mean; 34.3±33.3 ng/mL) and 0.20 to 56.7 ng/mL in nonmetastatic lymph nodes (mean; 4.9±11.1 ng/mL) (p<0.001). The most excellent diagnostic performance was displayed in 5 ng/mL of FNAB-Tg with AUC of 0.76, sensitivity, specificity, accuracy, 69.0, 83.0, and 76.8, respectively. However, there was no significant difference from 10 ng/mL FNAB.ConclusionWe ascertained that 5 ng/mL yielded the most excellent diagnostic performance among FNAB-Tg levels in the present setting with a large series with the indeterminate range (0.2-100 ng/mL) of FNAB-Tg values. These results need additional confirmation under different laboratory conditions.

Thyroglobulin measurement in fine‐needle aspirate washouts: the criteria for neck node dissection for patients with thyroid cancer

Several studies report that detection of thyroglobulin (Tg) in fine-needle aspiration (FNA) biopsy washout fluid from lymph nodes identifies recurrences/metastases of differentiated papillary thyroid cancer (DPTC) in the neck with higher sensitivity and specificity than fine-needle aspiration cytology (FNAC). However, the diagnostic FNA-Tg cutoff values have not yet been established. To determine an appropriate diagnostic threshold value for Tg levels in FNA washout fluid in patients with neck node metastases or recurrences of DPTC. We performed ultrasound (US)-guided FNAC and measured Tg levels in FNA washout fluid (FNA-Tg). Final diagnoses were confirmed by histological examination of excised specimens or by follow-up examinations for at least 24 months. A total of 168 ultrasonographically detected lymph nodes from 168 patients with DPTC were included. In comparison with FNAC, we evaluated diagnostic sensitivity, specificity and accuracy of metastasis detection according to several predetermined threshold levels: 1, 10, 100 ng/ml, mean+2SD of node-negative patients, and FNA-Tg/serum-Tg > 1. The diagnostic sensitivity was lowest at 77.3% for FNAC alone. The lower FNA-Tg threshold levels showed higher diagnostic sensitivity whereas the higher FNA-Tg showed higher specificity. In addition to the FNAC results, FNA-Tg levels showed 95.0% sensitivity, 81.6% specificity, 92.6% in positive predictive value (PPV) and 87.0% in negative predictive value (NPV) with the threshold of FNA-Tg level at 10 ng/ml, serum-Tg or mean+2SD of FNA-Tg measured in node-negative patients. The diagnostic accuracy of FNA-Tg was higher in neck node recurrences after thyroid surgery than in the metastasis of patients waiting for surgery. FNA-Tg measurement as well as FNAC should be performed either before or after surgery to evaluate neck node metastases or recurrences in patients with differentiated thyroid carcinomas. We recommend that the threshold values for FNA-Tg levels should be > 10 ng/ml if the serum-Tg level or the mean+2SD in node-negative patients is not available for reference.