Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer

Thyroglobulin (Tg) monitoring is the biochemical standard for surveillance of recurrent differentiated thyroid cancer (DTC). Several assays are available to quantify Tg levels: immunometric assay (IMA), radioimmunoassay (RIA), and the newer liquid chromatography tandem mass spectrometry (LC-MS). It...

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Main Authors: Michelle Ponder, Elizabeth Lamos, Kashif Munir
Format: Article
Language:English
Published: Wiley 2021-01-01
Series:Case Reports in Endocrinology
Online Access:http://dx.doi.org/10.1155/2021/1152572
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author Michelle Ponder
Elizabeth Lamos
Kashif Munir
author_facet Michelle Ponder
Elizabeth Lamos
Kashif Munir
author_sort Michelle Ponder
collection DOAJ
description Thyroglobulin (Tg) monitoring is the biochemical standard for surveillance of recurrent differentiated thyroid cancer (DTC). Several assays are available to quantify Tg levels: immunometric assay (IMA), radioimmunoassay (RIA), and the newer liquid chromatography tandem mass spectrometry (LC-MS). It is well known that a number of entities can interfere with the accuracy of testing, and at this point in time, no one assay perfectly balances high sensitivity with low risk of interference. In this case study, we present two cases in which treatment with desiccated thyroid extract (Armour thyroid) led to a sudden elevation in Tg, which resolved when Armour thyroid was discontinued. This elevation occurred when Tg was measured with both IMA and LC-MS, which suggests direct interference from porcine Tg rather than heterophilic or thyroglobulin antibody (TgAb) interference. We suggest that patients with a history of DTC not be treated with desiccated thyroid extracts consistent with guidelines. Furthermore, more advances need to be made in the area of Tg testing to improve specificity and avoid detection of nonhuman Tg and other similar proteins.
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spelling doaj-art-442ab023445e4ecdb8f09187de725fa72025-08-20T03:36:07ZengWileyCase Reports in Endocrinology2090-651X2021-01-01202110.1155/2021/1152572Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid CancerMichelle Ponder0Elizabeth Lamos1Kashif Munir2University of Maryland Medical CenterDivision of Endocrinology, Diabetes, and NutritionDivision of Endocrinology, Diabetes, and NutritionThyroglobulin (Tg) monitoring is the biochemical standard for surveillance of recurrent differentiated thyroid cancer (DTC). Several assays are available to quantify Tg levels: immunometric assay (IMA), radioimmunoassay (RIA), and the newer liquid chromatography tandem mass spectrometry (LC-MS). It is well known that a number of entities can interfere with the accuracy of testing, and at this point in time, no one assay perfectly balances high sensitivity with low risk of interference. In this case study, we present two cases in which treatment with desiccated thyroid extract (Armour thyroid) led to a sudden elevation in Tg, which resolved when Armour thyroid was discontinued. This elevation occurred when Tg was measured with both IMA and LC-MS, which suggests direct interference from porcine Tg rather than heterophilic or thyroglobulin antibody (TgAb) interference. We suggest that patients with a history of DTC not be treated with desiccated thyroid extracts consistent with guidelines. Furthermore, more advances need to be made in the area of Tg testing to improve specificity and avoid detection of nonhuman Tg and other similar proteins.http://dx.doi.org/10.1155/2021/1152572
spellingShingle Michelle Ponder
Elizabeth Lamos
Kashif Munir
Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
Case Reports in Endocrinology
title Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
title_full Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
title_fullStr Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
title_full_unstemmed Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
title_short Two Cases of Armour Thyroid Interference in Thyroglobulin Monitoring for Thyroid Cancer
title_sort two cases of armour thyroid interference in thyroglobulin monitoring for thyroid cancer
url http://dx.doi.org/10.1155/2021/1152572
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