title: Additional value of a high sensitive thyroglobulin assay in the follow-up of patients with differentiated thyroid carcinoma.
abstract: OBJECTIVE
  Thyroglobulin (Tg) is an excellent tumour marker, as detectable or increasing Tg levels are highly indicative of persistent or recurrent differentiated thyroid carcinoma (DTC). The clinical value of a highly sensitive (hs)-Tg assay in patients with DTC has not yet been established. The aim of this study was to investigate the additional value of unstimulated hs-Tg measurements (Tg-on) compared to stimulated IRMA-Tg measurements (Tg-off) in the follow-up of patients with DTC.
  
  
  METHODS
  We retrospectively studied patients treated for DTC between 2006 and 2013 and compared hs-Tg and IRMA-Tg measurements. The study group consisted of 99 DTC patients in remission; Tg-on was measured 3 months after remnant ablation and Tg-off 6 months after ablation.
  
  
  RESULTS
  In the study group, 44 patients showed a hs-Tg-on <0·15 μg/l (functional sensitivity); of these, 43 had an IRMA-Tg-off measurement <1·0 μg/l, resulting in a negative predictive value of 97·7% and a positive predictive value of 56·4%.
  
  
  CONCLUSIONS
  The hs-Tg-on measurement is able to predict patients with an IRMA-Tg-off <1·0 μg/l, and therefore decreases the need for Tg stimulation after ablation.
authors: Department of Endocrinology, University Medical Center Groningen, Groningen, The Netherlands.
authors: Andries H
authors: AH
authors: Groen
authors: Department of Endocrinology, University Medical Center Groningen, Groningen, The Netherlands.
authors: Mariëlle S
authors: MS
authors: Klein Hesselink
authors: Department of Surgical Oncology, University Medical Center Groningen, Groningen, The Netherlands.
authors: John T M
authors: JT
authors: Plukker
authors: Department of Endocrinology, University Medical Center Groningen, Groningen, The Netherlands.
authors: Wim J
authors: WJ
authors: Sluiter
authors: Department of Endocrinology, University Medical Center Groningen, Groningen, The Netherlands.
authors: Anouk N A
authors: AN
authors: van der Horst-Schrivers
authors: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen, The Netherlands.
authors: Adrienne H
authors: AH
authors: Brouwers
authors: Department of Clinical Chemistry and Hematology, Laboratory of Endocrinology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: Eef G W M
authors: EG
authors: Lentjes
authors: Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Anneke C
authors: AC
authors: Muller Kobold
authors: Department of Endocrinology, University Medical Center Groningen, Groningen, The Netherlands.
authors: Thera P
authors: TP
authors: Links
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood / Q000592:standards; D017115:Catheter Ablation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011237:Predictive Value of Tests; D012074:Remission Induction; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D013960:Thyroid Function Tests / Q000379:methods / Q000592:standards; D013964:Thyroid Neoplasms / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D013954:Thyroglobulin