Thyroglobulin Point of Care Assay for Rapid Detection of Metastatic Differentiated Thyroid Carcinoma: A Pilot Study
2Faculty of Health Science, Ben-Gurion University of the Negev
3Department of Biotechnology Engineering, Faculty of Engineering Science, Ben-Gurion University of the Negev
4Laboratory of Endocrinology, Soroka University Medical Center
5National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev
Introduction:
Fine needle aspiration (FNA) for thyroglobulin (Tg) measurement (FNA-Tg) and for cytology (FNAC) are recommended for the evaluation of cervical lymph nodes (LN) suspected as differentiated thyroid carcinoma (DTC) metastases.
Aim:
To assess the diagnostic accuracy of a novel point-of-care assay for Tg (POC-Tg) (Patent Application PCT/IL2022/050067), able to detect within minutes, Tg in the needle washout of a suspicious LN.
Methods:
Tg Limit of detection was set at a concentration of 5 ng/mL following needle dilution with 1 mL of 0.9% saline. The POC-Tg was assessed in the FNA clinic when a LN suspected as DTC metastasis was biopsied; and in the operating room (OR) when suspicious LN was found during thyroid surgery. Each LN was evaluated using both the formal method (FNA clinic- FNAC and FNA-Tg; OR- ‘frozen-section’), and the POC-Tg. Clinical decisions were made according to the formal evaluation. The POC-Tg performance was analyzed retrospectively.
Results:
FNA clinic: 22 LN were tested. Eleven were found to be positive in both our POC-Tg and the formal Tg immunoassay, with final histology reported metastatic DTC. Ten LN were negative in both our POC-Tg and the standard Tg immunoassay, all with benign cytology. One metastatic LN was negative in our POC-Tg but showed low detectable Tg in the standard immunoassay. OR: Four LNs were positive and seven negative in both our POC-Tg, and the ‘frozen-section’ results.
Conclusion:
The diagnostic accuracy of the POC-Tg for LN metastases of DTC origin exceeded 95%, thus it might improve diagnostic and treatment algorithms.
