Multicentre clinical evaluation of the new highly sensitive Elecsys? thyroglobulin II II assay in patients with differentiated thyroid carcinoma

摘要

Summary Objective A highly sensitive thyroglobulin assay (Elecsys? Tg II , Roche Diagnostics, Penzberg, Germany) has become available for monitoring patients with differentiated thyroid cancer ( DTC ). Here, we evaluated the clinical performance of Elecsys? Tg II assay in a multicentre patients series and compare it with the established Access? Tg assay (Beckman Coulter, Brea, CA, USA). Design Retrospective analysis on prospectively selected patients in four thyroid cancer referral centres with uniform DTC management. Participants All DTC cases diagnosed, treated and followed up in four tertiary referral centres for thyroid cancer since January 2005 (n?=?1456) were retrieved, and predefined selection criteria were applied to prevent relevant enrolment biases. A series of 204 patients was finally selected for this study. Measurements Samples had been stored at ?80°C. Tg was measured by fully automated immunometric Elecsys? Tg II and Access? Tg assays in a centralized laboratory. Results Two hundred and four DTC were finally included. Of these, 10.8% had structural recurrence ( sREC ), and 81.4% showed no evidence of disease ( NED ) at the end of follow‐up. There was a significant analytical bias between methods that cannot be used interchangeably. Using ROC curve analysis, the best basal and rh TSH ‐stimulated Tg cut‐offs to detect sREC were 0.41?μg/L and 1.82?μg/L for Elecsys? and 0.36?μg/L and 1.62?μg/L for Access? assay, respectively. Using Cox proportional hazard regression, Tg was the only independent predictor of cancer relapse. Conclusions Using appropriate assay‐specific cut‐offs, the clinical performance of the Elecsys? Tg II assay was comparable to that provided by the well‐established Access? Tg assay.