title: Serum Thyroglobulin Measured With a Second-Generation Assay in Patients Undergoing Total Thyroidectomy Without Radioiodine Remnant Ablation: A Prospective Study.
abstract: BACKGROUND
  Follow-up consisting of the measurement of nonstimulated serum thyroglobulin (Tg) combined with neck ultrasonography is recommended for patients with papillary thyroid carcinoma without indication for radioiodine ablation. There is no recommendation of thyrotropin suppression during this follow-up. New-generation Tg assays have been increasingly used, but few studies involve patients submitted only to thyroidectomy and they have several limitations. The objective of this prospective study was to define expected concentrations of nonstimulated Tg measured with a second-generation assay after total thyroidectomy in the absence of tumor.
  
  
  METHODS
  Serum Tg was measured using a second-generation assay in 69 patients without tumor and serum thyrotropin between 0.5 and 2 mIU/L, 3, 6, 12, and 24 months after total thyroidectomy. All patients had undetectable anti-Tg antibodies.
  
  
  RESULTS
  Serum Tg was undetectable in 44.4%, 57%, 62.5%, and 62.1% of the patients 3, 6, 12, and 24 months after thyroidectomy, respectively, and was ≤0.5 ng/mL in 60.3%, 80%, 90.6%, and 90.9% of patients. All patients had a Tg≤2 ng/mL 6 months after thyroidectomy, and 97% had a Tg≤1 ng/mL 24 months after surgery. There was no case of Tg conversion from undetectable to detectable and none of the patients presented an increase in Tg.
  
  
  CONCLUSIONS
  An important decline in serum Tg occurred between 3 and 6 months after total thyroidectomy. One year after surgery, Tg was undetectable in approximately 60% of the patients and was ≤2 ng/mL in all of them.
authors.affiliation: 1 Postgraduate Program, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .|2 Endocrinology Service, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .
authors.forename: Pedro Weslley
authors.initials: PW
authors.lastname: Rosario
authors.affiliation: 1 Postgraduate Program, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .|2 Endocrinology Service, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .
authors.forename: Gabriela Franco
authors.initials: GF
authors.lastname: Mourão
authors.affiliation: 1 Postgraduate Program, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .
authors.forename: Thássio Leonardo
authors.initials: TL
authors.lastname: Siman
authors.affiliation: 2 Endocrinology Service, Santa Casa de Belo Horizonte , Minas Gerais, Brazil .
authors.forename: Maria Regina
authors.initials: MR
authors.lastname: Calsolari
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery; D018278:Carcinoma, Neuroendocrine / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery; D002291:Carcinoma, Papillary; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000000981:diagnostic imaging; D011184:Postoperative Period; D011446:Prospective Studies; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery; D016606:Thyroid Nodule / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood; D018608:Ultrasonography, Doppler; D055815:Young Adult
chemical_list: D013972:Thyrotropin; D013954:Thyroglobulin