Development, characterization and clinical validation of new sensitive immunofluorometric assay for the measurement of serum thyroglobulin

Abstract

OBJECTIVE: In the last decade, data published stressed the role of highly-sensitive thyroglobulin (Tg) assays in the follow-up of differentiated thyroid carcinoma (DTC) patients. The present study describes a new, highly-sensitive Tg assay, compares it with an available commercial assay, and validates it in the follow-up of DTC patients. SUBJECTS AND METHODS: The immunofluorometric high-sensitivity Tg assay is based on monoclonal and polyclonal antibodies produced at our laboratories. It was validated in 100 samples of 87 patients with DTC submitted to total thyroidectomy, 87% of whom also received radioiodine. For correlation, all samples were also tested using a commercial Tg assay (Beckman Access) with functional sensitivity (FS) of 0.1 ng/mL. RESULTS: The new method showed FS of 0.3 ng/mL. The correlation between the two methods was good (r = 0.74; p < 0.0001). The diagnostic sensitivity was 88.9%, and it was increased to 100% when combined with neck US. CONCLUSION: This new, high-sensitivity Tg assay presented a good correlation with Beckman Access assay and with the clinical outcome of the patients. The continuous availability of a validated assay is an additional advantage for long term follow-up of DTC patients. Arq Bras Endocrinol Metab. 2012;56(9):658-65

Basal Serum Thyroglobulin Measured by a Second-Generation Assay Is Equivalent to Stimulated Thyroglobulin in Identifying Metastases in Patients with Differentiated Thyroid Cancer with Low or Intermediate Risk of Recurrence

“…Between-run precision assessed over a period of 12 months was 1.7, 1.8, 4.9 and 4.0% for the same pools. The total CV was 4.9% for a pool with a mean value of 4.2 ng/ml, 5.2% for a pool with a mean value of 5.3 ng/ml, 6.4% for a pool with a mean value of 34.0 ng/ml, 3.8% for a control with a mean value of 42.5 ng/ml and 4.6% for a control with a mean value of 213.0 ng/ml [26]. This assay is referred to throughout this study as ‘Tg2GICMA'.…”

Additional value of a high sensitive thyroglobulin assay in the follow-up of patients with differentiated thyroid carcinoma

“…Tg Access assay [Beckman Coulter] and ELISA EIASON TgCa [IASON GmbH]), varying between 97% and 100% (95% CI: 98-100). 8,[14][15][16][17][18] The value of hs-Tg assays has usually been studied during long-term follow-up comparing a hs-Tg-on with a rhTSHstimulated Tg measurement, whereas our data evaluate the hs-Tgon measurement in comparison with Tg values during THW, a more intense way of TSH stimulation. 19 The NPV of 97Á7% during THW shows the strength of this hs-Tg KRYPTOR assay.…”

Clinical impact of thyroglobulin (Tg) and Tg autoantibody (TgAb) measurements in needle washouts of neck lymph node biopsies in the management of patients with papillary thyroid carcinoma

“…A second immunofluorometric Tg assay (assay 2), using mono and polyclonal antibodies, was performed on the washout fluids of sTgAb+ patients with a Tg-FNAB value < 10 ng/mL in assay 1 to determine whether low Tg-FNAB persisted using a different method. Assay 2 has a functional sensitivity of 0.3 ng/mL (28). The Tg assay 2 was assessed only in this specific group of patients for whom the TgAb-FNAB results, in the case of positivity by contamination with sTgAb, could interfere with the Tg-FNAB levels.…”