Thyroglobulin wash testing in the surveillance of patients with thyroid carcinoma: proposal for a reflex test

Fine needle aspiration (FNA) cytology with thyroglobulin wash (TG-W) testing is recommended for follow-up of patients with differentiated thyroid carcinoma (DTC). The goal of this retrospective study was to determine if TG-W results contributed to the management of cases with positive FNA cytology.

We reviewed data on patients with positive and suspicious cytology results, undergoing lymph node or thyroid bed FNA with TG-W testing as part of the preoperative or follow-up investigation of histologically proven DTC in our institution and from the literature.

Of 30 positive/suspicious lymph node and thyroid bed FNAs in our institution, 22 (73%) had an elevated (>1 ng/ml) TG-W level. Seven of 8 TG-W-negative cases had DTC on follow-up. Of 577 cytology-positive/suspicious FNAs in the literature, 557 (97%) showed TG-W-positive results. Fourteen of 20 TG-W-negative cases had DTC on follow-up. All patients in retrospective and literature review groups with positive and suspicious FNA cytology and available follow-up were treated for recurrent or metastatic disease regardless of TG-W results.

Observations of both our and other institutions support a recommendation of reflex FNA TG-W testing only for cases with negative or indeterminate cytology results.