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Erzsébet Toldy - One of the best experts on this subject based on the ideXlab platform.
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Serum Thyroglobulin Antibody levels within or near to the reference range may interfere with Thyroglobulin measurement
Biochemia medica, 2012Co-Authors: Zoltan Locsei, István Szabolcs, Károly Rácz, Gábor L. Kovács, Dóra Horváth, Erzsébet ToldyAbstract:High concentration of Thyroglobulin antibodies (TgAb) is a major limiting factor of Thyroglobulin measurements in patients with differentiated thyroid cancer. We investigated whether Thyroglobulin Antibody added to serum samples could interfere with the Thyroglobulin assay. Thyroglobulin levels in serum samples with different concentrations of Thyroglobulin were measured by electrochemiluminescence immunoassay before and after the addition of increasing concentrations of Thyroglobulin Antibody using the secondary calibrator solution of the Thyroglobulin assay kit containing sheep Thyroglobulin Antibody to reach Thyroglobulin Antibody levels within or near to the reference range. Thyroglobulin and Thyroglobulin Antibody concentrations were also measured in 134 serum samples from 27 patients after thyroid ablation. There was a strong negative association (slope = -1.179) between Thyroglobulin Antibody and Thyroglobulin concentrations in samples with added Thyroglobulin Antibody (beta = -0.86; P < 0.001). Changes in Thyroglobulin concentrations were described mathematically as loss of Thyroglobulin% = -0.2408 x Ln(Thyroglobulin Antibody IU/ml) + 0.1944. Thyroglobulin concentrations were significantly lower than those calculated from experiments with added Thyroglobulin Antibody in 26/134 samples from patients after thyroid ablation. We conclude that if the same TgAb interference exists in the presence of naturally occurring human TgAb, our observation may prove to be useful during follow-up of patients with differentiated thyroid cancer. However, further studies are needed to explore the clinical relevance of Thyroglobulin Antibody levels within or near to the reference range in monitoring these patients.
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Szérumtireoglobulin és tireoglobulin-antitest együttesmeghatározásának jelentősége a differenciált pajzsmirigy-karcinómás betegek gondozása során = The significance of simultaneous measurement of serum Thyroglobulin and Thyroglobulin Antibody during
2011Co-Authors: Zoltán Lőcsei, Károly Rácz, Dóra Horváth, Erzsébet ToldyAbstract:A differencialt pajzsmirigy-karcinomas betegek gondozasaban a szerumtireoglobulin alapvető tumormarker. A tireoglobulin teljes hianyat nem lehet bizonyitani immunanalitikai modszerekkel, ha a beteg szerumaban tireoglobulin ellen kepződő autoantitest van jelen, ami differencialt pajzsmirigy-karcinomaban szenvedő betegek kozel 20%-aban előfordul. Ezert a szakmai ajanlasok csak a tireoglobulin-autoantitest mennyisegenek ismereteben javasoljak a szerumtireoglobulin-lelet ertekeleset. A tireoglobulin-autoantitest normalis szintje nem zarja ki a zavaro hatast, ugyanis nem ismert, hogy mekkora antitest-koncentracional nem kell antitest-interakcioval szamolnunk. Ebben a tekintetben nem kovetkezetesek az irodalmi ajanlasok, mivel ritkan tesznek kulonbseget a tireoglobulinautoantitest-negativitas es az alacsony, de meg merhető antitestszint kozott. Ezert nem egyertelmű, hogy az alacsony antitestszintek mennyire befolyasoljak a tireoglobulin kimutathatosagat. A szerzők az irodalmi adatok es szakmai ajanlasok tukreben tekintik at a szerumtireoglobulin- es tireoglobulinautoantitest-vizsgalat preanalitikai es analitikai korlatait, es sajat eredmenyeik alapjan javaslatot tesznek a tireoglobulinmeghatarozas diagnosztikai pontossaganak novelesere. Orv. Hetil., 2011, 152, 743–752. | Serum Thyroglobulin is an essential marker during the follow-up of patients with differentiated thyroid carcinoma. Demonstration of the total absence of Thyroglobulin is not possible by immunoanalytic methods if Thyroglobulin Antibody is present in serum samples that occur in almost 20% of patients with differentiated thyroid carcinoma. Therefore, current guidelines recommend estimation of Thyroglobulin levels only if quantitative level of Thyroglobulin Antibody is known. However, normal Thyroglobulin Antibody level fails to exclude interference with the Antibody, because Antibody concentration within the normal range may interfere with the Thyroglobulin assay. In this respect recommendations are not consistent because they distinguish only occasionally cases with normal and those with non-detectable serum Thyroglobulin level. In addition, the possible impact of normal Thyroglobulin Antibody level on the Thyroglobulin assay has not been entirely explored. Authors review literature data and current guidelines on the analytical and preanalytical limitations of the Thyroglobulin and Thyroglobulin Antibody measurements. On the basis of their own studies, authors make recommendation for improvement of the diagnostic accuracy of the Thyroglobulin measurement. Orv. Hetil., 2011, 152, 743–752.
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szerumtireoglobulin es tireoglobulin antitest egyuttesmeghatarozasanak jelentősege a differencialt pajzsmirigy karcinomas betegek gondozasa soran the significance of simultaneous measurement of serum Thyroglobulin and Thyroglobulin Antibody during th
2011Co-Authors: Zoltán Lőcsei, Károly Rácz, Dóra Horváth, Erzsébet ToldyAbstract:A differencialt pajzsmirigy-karcinomas betegek gondozasaban a szerumtireoglobulin alapvető tumormarker. A tireoglobulin teljes hianyat nem lehet bizonyitani immunanalitikai modszerekkel, ha a beteg szerumaban tireoglobulin ellen kepződő autoantitest van jelen, ami differencialt pajzsmirigy-karcinomaban szenvedő betegek kozel 20%-aban előfordul. Ezert a szakmai ajanlasok csak a tireoglobulin-autoantitest mennyisegenek ismereteben javasoljak a szerumtireoglobulin-lelet ertekeleset. A tireoglobulin-autoantitest normalis szintje nem zarja ki a zavaro hatast, ugyanis nem ismert, hogy mekkora antitest-koncentracional nem kell antitest-interakcioval szamolnunk. Ebben a tekintetben nem kovetkezetesek az irodalmi ajanlasok, mivel ritkan tesznek kulonbseget a tireoglobulinautoantitest-negativitas es az alacsony, de meg merhető antitestszint kozott. Ezert nem egyertelmű, hogy az alacsony antitestszintek mennyire befolyasoljak a tireoglobulin kimutathatosagat. A szerzők az irodalmi adatok es szakmai ajanlasok tukreben tekintik at a szerumtireoglobulin- es tireoglobulinautoantitest-vizsgalat preanalitikai es analitikai korlatait, es sajat eredmenyeik alapjan javaslatot tesznek a tireoglobulinmeghatarozas diagnosztikai pontossaganak novelesere. Orv. Hetil., 2011, 152, 743–752. | Serum Thyroglobulin is an essential marker during the follow-up of patients with differentiated thyroid carcinoma. Demonstration of the total absence of Thyroglobulin is not possible by immunoanalytic methods if Thyroglobulin Antibody is present in serum samples that occur in almost 20% of patients with differentiated thyroid carcinoma. Therefore, current guidelines recommend estimation of Thyroglobulin levels only if quantitative level of Thyroglobulin Antibody is known. However, normal Thyroglobulin Antibody level fails to exclude interference with the Antibody, because Antibody concentration within the normal range may interfere with the Thyroglobulin assay. In this respect recommendations are not consistent because they distinguish only occasionally cases with normal and those with non-detectable serum Thyroglobulin level. In addition, the possible impact of normal Thyroglobulin Antibody level on the Thyroglobulin assay has not been entirely explored. Authors review literature data and current guidelines on the analytical and preanalytical limitations of the Thyroglobulin and Thyroglobulin Antibody measurements. On the basis of their own studies, authors make recommendation for improvement of the diagnostic accuracy of the Thyroglobulin measurement. Orv. Hetil., 2011, 152, 743–752.
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The effect of sample storage on the reliability of Thyroglobulin and Thyroglobulin-Antibody measurements.
Clinical biochemistry, 2008Co-Authors: Zoltan Locsei, István Szabolcs, Károly Rácz, Erzsébet Toldy, Gábor L. KovácsAbstract:Abstract Objectives To investigate how sample-storage alters Thyroglobulin (Tg) and Thyroglobulin-Antibody (TgAb) immunoreactivity. Design and methods Tg and TgAb measurements at different storage-times and -temperatures. Results 48-h-storage at 4–10 °C (but not 8 h at room temperature) increased Tg and decreased TgAb immunoreactivity by maximum + 23% and − 16%. 4-weeks-storage at − 17 to − 20 °C decreased both Tg and TgAb by max. 21–31%. Conclusions Storage of samples at 4–10 °C for > 24–48 h, or at − 17 to − 20 °C for > 2–3 weeks significantly alters Tg and TgAb immunoreactivity.
John Lazarus - One of the best experts on this subject based on the ideXlab platform.
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Prognostic Significance of Thyroglobulin Antibody Epitopes in Differentiated Thyroid Cancer
The Journal of clinical endocrinology and metabolism, 2015Co-Authors: Giovanni Lupoli, Onyebuchi E. Okosieme, C. Evans, P. M. Clark, A. J. Pickett, Lakdassa D. K. E. Premawardhana, John LazarusAbstract:Context: Thyroglobulin antibodies (TgAbs) are surrogate markers of disease recurrence or persistence in differentiated thyroid cancer (DTC). However, the prognostic significance of TgAb heterogeneity in DTC has not been investigated. Objective: To evaluate the relationship between TgAb epitope specificities and clinical outcomes in DTC patients. Design: We studied 61 TgAb-positive patients with DTC, post-thyroidectomy and remnant ablation (7 males, 54 females; age-range 16–80 years, median follow-up duration 8.9 years). TgAb epitope reactivities were mapped using a panel of 10 Thyroglobulin (Tg) monoclonal antibodies delineating six antigenic Tg clusters in competitive ELISA studies. Sera from 45 patients with Hashimoto's thyroiditis (HT) and 22 TgAb-positive healthy subjects served as autoimmune and healthy controls. Tg was measured by immunoradiometric assay (IRMA), electrochemiluminescence immunoassay (ECLIA), and RIA, while TgAbs was measured by ELISA and ECLIA methods. Results: Samples from 26 DTC patients showed TgAb epitope restriction similar to HT patients, while 35 patients exhibited nonspecific reactivity comparable to healthy controls. DTC patients with epitope restriction had higher rates of recurrent/persistent disease (81% vs 17%, P < .001), higher median TgAb concentration (887.0 vs 82.0 kIU/L; P < .001), and a higher prevalence of thyroid lymphocytic infiltration (71.4% vs 26.8%; P < .001) compared to patients with nonspecific reactivity. Samples with epitope restriction also had a lower median Tg-IRMA/RIA ratio (3.0% vs 36.0%; P < .001) denoting greater degrees of Tg assay interference. Conclusions: TgAb epitope restriction is associated with a less favorable prognosis than nonspecific reactivity in DTC patients. TgAb epitope specificities may have prognostic value in DTC
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Restricted Thyroglobulin Antibody epitope specificities in subjects with type 1 diabetes mellitus.
European journal of endocrinology, 2009Co-Authors: Onyebuchi E. Okosieme, John Lazarus, Chandrika N. Wijeyaratne, Lakdassa D. K. E. PremawardhanaAbstract:Objectives Following iodisation in Sri Lanka we observed a high prevalence of Thyroglobulin antibodies (TgAbs) in type 1 diabetic (T1DM) patients. The clinical significance of these TgAbs is uncertain. We sought to obtain a detailed epitope analysis of TgAbs in T1DM patients recruited from diabetes clinics and to compare these with TgAb epitope specificities in patients with autoimmune thyroid disease (AITD) and healthy individuals in that country. Design and methods We used a panel of 10 Tg-MAbs in competitive ELISA reactions in a prospective study of subjects recruited from Colombo, to determine the epitopes recognised by TgAb-positive patients with T1DM (n=58, 34F:24M, median age 16 years), AITD patients (n=42, 33F:9M, median age 37 years) and healthy subjects (n=50, 39F:11M, median age 27 years). The outcomes were a comparison of reactivity with six Tg clusters (I–VI) in these subjects, and the relation of epitope specificity patterns with free thyroxine and TSH. Results Patients with T1DM and AITD but not healthy control subjects preferentially recognised the immunodominant clusters, I, III and IV. Patients with these narrow epitope specificities had higher median TSH levels (1.60 vs 1.06; P=0.01), and were more frequently positive for antibodies to thyroid peroxidase than those with broad specificities (52.3 vs 7.1%; P=0.004). Conclusions The TgAb epitope specificities in euthyroid Sri Lankans with T1DM are similar to AITD patients. TgAb epitope studies may potentially identify T1DM patients at risk of thyroid dysfunction.
Lakdassa D. K. E. Premawardhana - One of the best experts on this subject based on the ideXlab platform.
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Prognostic Significance of Thyroglobulin Antibody Epitopes in Differentiated Thyroid Cancer
The Journal of clinical endocrinology and metabolism, 2015Co-Authors: Giovanni Lupoli, Onyebuchi E. Okosieme, C. Evans, P. M. Clark, A. J. Pickett, Lakdassa D. K. E. Premawardhana, John LazarusAbstract:Context: Thyroglobulin antibodies (TgAbs) are surrogate markers of disease recurrence or persistence in differentiated thyroid cancer (DTC). However, the prognostic significance of TgAb heterogeneity in DTC has not been investigated. Objective: To evaluate the relationship between TgAb epitope specificities and clinical outcomes in DTC patients. Design: We studied 61 TgAb-positive patients with DTC, post-thyroidectomy and remnant ablation (7 males, 54 females; age-range 16–80 years, median follow-up duration 8.9 years). TgAb epitope reactivities were mapped using a panel of 10 Thyroglobulin (Tg) monoclonal antibodies delineating six antigenic Tg clusters in competitive ELISA studies. Sera from 45 patients with Hashimoto's thyroiditis (HT) and 22 TgAb-positive healthy subjects served as autoimmune and healthy controls. Tg was measured by immunoradiometric assay (IRMA), electrochemiluminescence immunoassay (ECLIA), and RIA, while TgAbs was measured by ELISA and ECLIA methods. Results: Samples from 26 DTC patients showed TgAb epitope restriction similar to HT patients, while 35 patients exhibited nonspecific reactivity comparable to healthy controls. DTC patients with epitope restriction had higher rates of recurrent/persistent disease (81% vs 17%, P < .001), higher median TgAb concentration (887.0 vs 82.0 kIU/L; P < .001), and a higher prevalence of thyroid lymphocytic infiltration (71.4% vs 26.8%; P < .001) compared to patients with nonspecific reactivity. Samples with epitope restriction also had a lower median Tg-IRMA/RIA ratio (3.0% vs 36.0%; P < .001) denoting greater degrees of Tg assay interference. Conclusions: TgAb epitope restriction is associated with a less favorable prognosis than nonspecific reactivity in DTC patients. TgAb epitope specificities may have prognostic value in DTC
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Restricted Thyroglobulin Antibody epitope specificities in subjects with type 1 diabetes mellitus.
European journal of endocrinology, 2009Co-Authors: Onyebuchi E. Okosieme, John Lazarus, Chandrika N. Wijeyaratne, Lakdassa D. K. E. PremawardhanaAbstract:Objectives Following iodisation in Sri Lanka we observed a high prevalence of Thyroglobulin antibodies (TgAbs) in type 1 diabetic (T1DM) patients. The clinical significance of these TgAbs is uncertain. We sought to obtain a detailed epitope analysis of TgAbs in T1DM patients recruited from diabetes clinics and to compare these with TgAb epitope specificities in patients with autoimmune thyroid disease (AITD) and healthy individuals in that country. Design and methods We used a panel of 10 Tg-MAbs in competitive ELISA reactions in a prospective study of subjects recruited from Colombo, to determine the epitopes recognised by TgAb-positive patients with T1DM (n=58, 34F:24M, median age 16 years), AITD patients (n=42, 33F:9M, median age 37 years) and healthy subjects (n=50, 39F:11M, median age 27 years). The outcomes were a comparison of reactivity with six Tg clusters (I–VI) in these subjects, and the relation of epitope specificity patterns with free thyroxine and TSH. Results Patients with T1DM and AITD but not healthy control subjects preferentially recognised the immunodominant clusters, I, III and IV. Patients with these narrow epitope specificities had higher median TSH levels (1.60 vs 1.06; P=0.01), and were more frequently positive for antibodies to thyroid peroxidase than those with broad specificities (52.3 vs 7.1%; P=0.004). Conclusions The TgAb epitope specificities in euthyroid Sri Lankans with T1DM are similar to AITD patients. TgAb epitope studies may potentially identify T1DM patients at risk of thyroid dysfunction.
Giovanni Lupoli - One of the best experts on this subject based on the ideXlab platform.
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Prognostic Significance of Thyroglobulin Antibody Epitopes in Differentiated Thyroid Cancer
The Journal of clinical endocrinology and metabolism, 2015Co-Authors: Giovanni Lupoli, Onyebuchi E. Okosieme, C. Evans, P. M. Clark, A. J. Pickett, Lakdassa D. K. E. Premawardhana, John LazarusAbstract:Context: Thyroglobulin antibodies (TgAbs) are surrogate markers of disease recurrence or persistence in differentiated thyroid cancer (DTC). However, the prognostic significance of TgAb heterogeneity in DTC has not been investigated. Objective: To evaluate the relationship between TgAb epitope specificities and clinical outcomes in DTC patients. Design: We studied 61 TgAb-positive patients with DTC, post-thyroidectomy and remnant ablation (7 males, 54 females; age-range 16–80 years, median follow-up duration 8.9 years). TgAb epitope reactivities were mapped using a panel of 10 Thyroglobulin (Tg) monoclonal antibodies delineating six antigenic Tg clusters in competitive ELISA studies. Sera from 45 patients with Hashimoto's thyroiditis (HT) and 22 TgAb-positive healthy subjects served as autoimmune and healthy controls. Tg was measured by immunoradiometric assay (IRMA), electrochemiluminescence immunoassay (ECLIA), and RIA, while TgAbs was measured by ELISA and ECLIA methods. Results: Samples from 26 DTC patients showed TgAb epitope restriction similar to HT patients, while 35 patients exhibited nonspecific reactivity comparable to healthy controls. DTC patients with epitope restriction had higher rates of recurrent/persistent disease (81% vs 17%, P < .001), higher median TgAb concentration (887.0 vs 82.0 kIU/L; P < .001), and a higher prevalence of thyroid lymphocytic infiltration (71.4% vs 26.8%; P < .001) compared to patients with nonspecific reactivity. Samples with epitope restriction also had a lower median Tg-IRMA/RIA ratio (3.0% vs 36.0%; P < .001) denoting greater degrees of Tg assay interference. Conclusions: TgAb epitope restriction is associated with a less favorable prognosis than nonspecific reactivity in DTC patients. TgAb epitope specificities may have prognostic value in DTC
Onyebuchi E. Okosieme - One of the best experts on this subject based on the ideXlab platform.
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Prognostic Significance of Thyroglobulin Antibody Epitopes in Differentiated Thyroid Cancer
The Journal of clinical endocrinology and metabolism, 2015Co-Authors: Giovanni Lupoli, Onyebuchi E. Okosieme, C. Evans, P. M. Clark, A. J. Pickett, Lakdassa D. K. E. Premawardhana, John LazarusAbstract:Context: Thyroglobulin antibodies (TgAbs) are surrogate markers of disease recurrence or persistence in differentiated thyroid cancer (DTC). However, the prognostic significance of TgAb heterogeneity in DTC has not been investigated. Objective: To evaluate the relationship between TgAb epitope specificities and clinical outcomes in DTC patients. Design: We studied 61 TgAb-positive patients with DTC, post-thyroidectomy and remnant ablation (7 males, 54 females; age-range 16–80 years, median follow-up duration 8.9 years). TgAb epitope reactivities were mapped using a panel of 10 Thyroglobulin (Tg) monoclonal antibodies delineating six antigenic Tg clusters in competitive ELISA studies. Sera from 45 patients with Hashimoto's thyroiditis (HT) and 22 TgAb-positive healthy subjects served as autoimmune and healthy controls. Tg was measured by immunoradiometric assay (IRMA), electrochemiluminescence immunoassay (ECLIA), and RIA, while TgAbs was measured by ELISA and ECLIA methods. Results: Samples from 26 DTC patients showed TgAb epitope restriction similar to HT patients, while 35 patients exhibited nonspecific reactivity comparable to healthy controls. DTC patients with epitope restriction had higher rates of recurrent/persistent disease (81% vs 17%, P < .001), higher median TgAb concentration (887.0 vs 82.0 kIU/L; P < .001), and a higher prevalence of thyroid lymphocytic infiltration (71.4% vs 26.8%; P < .001) compared to patients with nonspecific reactivity. Samples with epitope restriction also had a lower median Tg-IRMA/RIA ratio (3.0% vs 36.0%; P < .001) denoting greater degrees of Tg assay interference. Conclusions: TgAb epitope restriction is associated with a less favorable prognosis than nonspecific reactivity in DTC patients. TgAb epitope specificities may have prognostic value in DTC
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Restricted Thyroglobulin Antibody epitope specificities in subjects with type 1 diabetes mellitus.
European journal of endocrinology, 2009Co-Authors: Onyebuchi E. Okosieme, John Lazarus, Chandrika N. Wijeyaratne, Lakdassa D. K. E. PremawardhanaAbstract:Objectives Following iodisation in Sri Lanka we observed a high prevalence of Thyroglobulin antibodies (TgAbs) in type 1 diabetic (T1DM) patients. The clinical significance of these TgAbs is uncertain. We sought to obtain a detailed epitope analysis of TgAbs in T1DM patients recruited from diabetes clinics and to compare these with TgAb epitope specificities in patients with autoimmune thyroid disease (AITD) and healthy individuals in that country. Design and methods We used a panel of 10 Tg-MAbs in competitive ELISA reactions in a prospective study of subjects recruited from Colombo, to determine the epitopes recognised by TgAb-positive patients with T1DM (n=58, 34F:24M, median age 16 years), AITD patients (n=42, 33F:9M, median age 37 years) and healthy subjects (n=50, 39F:11M, median age 27 years). The outcomes were a comparison of reactivity with six Tg clusters (I–VI) in these subjects, and the relation of epitope specificity patterns with free thyroxine and TSH. Results Patients with T1DM and AITD but not healthy control subjects preferentially recognised the immunodominant clusters, I, III and IV. Patients with these narrow epitope specificities had higher median TSH levels (1.60 vs 1.06; P=0.01), and were more frequently positive for antibodies to thyroid peroxidase than those with broad specificities (52.3 vs 7.1%; P=0.004). Conclusions The TgAb epitope specificities in euthyroid Sri Lankans with T1DM are similar to AITD patients. TgAb epitope studies may potentially identify T1DM patients at risk of thyroid dysfunction.