Improvement in the Detection of Cystic Metastatic Papillary Thyroid Carcinoma by Measurement of Thyroglobulin in Aspirated Fluid

Table 2

Evaluation of metastatic PTC according to the diagnostic modality.

Modalities	SN	SP	PPV	NPV	AC
FNAC	80.0%	100%	100%	81.4%	89.3%
Tg-FNA	97.5%	97.1%	97.5%	97.1%	97.3%
FNAC + Tg-FNA	97.5%	100%	100%	97.1%	98.7%

Tg-FNA refers to the optimal cutoff value of Tg-FNA at 77.0 ng/mL.
Positive result was determined if the positive criteria for either criterion were met except in one special case. In this case, the Tg level was positive (>500 ng/mL), but the definitive cytological diagnosis was thyroglossal cyst. Accordingly, a diagnosis of thyroglossal cyst with a high Tg level was a reasonable diagnosis. This case was considered negative when performing statistical analyses of the combined criteria. SN, sensitivity; SP, specificity; PPV, positive predictive value; NPV, negative predictive value; AC, accuracy.