Laboratory evaluation of thyroid function: Dilemmas and pitfalls

Among all endocrine disorders, thyroid dysfunction is possibly most common endocrine disorder barring obesity. This implies that thyroid function tests (TFT) are routinely ordered for laboratory test for its evaluation. Furthermore, recently laboratory values of thyroid function, thyroid-stimulating...

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Main Authors: M K Garg, Namita Mahalle, K.V. S. Hari Kumar
Format: Article
Language:English
Published: Wolters Kluwer Medknow Publications 2016-01-01
Series:Medical Journal of Dr. D.Y. Patil University
Subjects:
Online Access:http://www.mjdrdypu.org/article.asp?issn=0975-2870;year=2016;volume=9;issue=4;spage=430;epage=436;aulast=Garg
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author M K Garg
Namita Mahalle
K.V. S. Hari Kumar
author_facet M K Garg
Namita Mahalle
K.V. S. Hari Kumar
author_sort M K Garg
collection DOAJ
description Among all endocrine disorders, thyroid dysfunction is possibly most common endocrine disorder barring obesity. This implies that thyroid function tests (TFT) are routinely ordered for laboratory test for its evaluation. Furthermore, recently laboratory values of thyroid function, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), have gathered importance in view of rapidly changing cut-offs for treatment of thyroid disorders during pregnancy. Most of the times, interpretation of TFT is easy, indicating euthyroidism (normal FT4 and TSH), hypothyroidism (low FT4 or FT3 with high TSH), or thyrotoxicosis (high FT4 or FT3 with low TSH). However, the normal ranges reflect two standard deviations around the mean. Hence, 2.5% of the population may show minor abnormalities on both side of normal range in spite of being euthyroid. Sometimes interpretation becomes difficult when there is an alteration in relation between thyroid hormones and TSH. These pitfalls in investigations will cause dilemma in physicians and patients mind alike. Problems in hormonal evaluation can be preanalytical, analytical, and postanalytical. In an ambulatory patient, TFTs have limited preanalytical interferences such as age, pregnancy, medications, genetic mutations, systemic diseases, and critical illnesses. Analytical errors occur due to heterophile antibodies and macro-TSH. Postanalytical errors include wrong entry of the result, mistakes in the units of the parameter checked and failure to identify the normal data.
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spelling doaj.art-e97b7f14628342458426c36d6800a61b2022-12-22T00:46:54ZengWolters Kluwer Medknow PublicationsMedical Journal of Dr. D.Y. Patil University0975-28702016-01-019443043610.4103/0975-2870.186054Laboratory evaluation of thyroid function: Dilemmas and pitfallsM K GargNamita MahalleK.V. S. Hari KumarAmong all endocrine disorders, thyroid dysfunction is possibly most common endocrine disorder barring obesity. This implies that thyroid function tests (TFT) are routinely ordered for laboratory test for its evaluation. Furthermore, recently laboratory values of thyroid function, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), have gathered importance in view of rapidly changing cut-offs for treatment of thyroid disorders during pregnancy. Most of the times, interpretation of TFT is easy, indicating euthyroidism (normal FT4 and TSH), hypothyroidism (low FT4 or FT3 with high TSH), or thyrotoxicosis (high FT4 or FT3 with low TSH). However, the normal ranges reflect two standard deviations around the mean. Hence, 2.5% of the population may show minor abnormalities on both side of normal range in spite of being euthyroid. Sometimes interpretation becomes difficult when there is an alteration in relation between thyroid hormones and TSH. These pitfalls in investigations will cause dilemma in physicians and patients mind alike. Problems in hormonal evaluation can be preanalytical, analytical, and postanalytical. In an ambulatory patient, TFTs have limited preanalytical interferences such as age, pregnancy, medications, genetic mutations, systemic diseases, and critical illnesses. Analytical errors occur due to heterophile antibodies and macro-TSH. Postanalytical errors include wrong entry of the result, mistakes in the units of the parameter checked and failure to identify the normal data.http://www.mjdrdypu.org/article.asp?issn=0975-2870;year=2016;volume=9;issue=4;spage=430;epage=436;aulast=GargHypothyroidismthyroid function teststhyroxinetriiodothyronine
spellingShingle M K Garg
Namita Mahalle
K.V. S. Hari Kumar
Laboratory evaluation of thyroid function: Dilemmas and pitfalls
Medical Journal of Dr. D.Y. Patil University
Hypothyroidism
thyroid function tests
thyroxine
triiodothyronine
title Laboratory evaluation of thyroid function: Dilemmas and pitfalls
title_full Laboratory evaluation of thyroid function: Dilemmas and pitfalls
title_fullStr Laboratory evaluation of thyroid function: Dilemmas and pitfalls
title_full_unstemmed Laboratory evaluation of thyroid function: Dilemmas and pitfalls
title_short Laboratory evaluation of thyroid function: Dilemmas and pitfalls
title_sort laboratory evaluation of thyroid function dilemmas and pitfalls
topic Hypothyroidism
thyroid function tests
thyroxine
triiodothyronine
url http://www.mjdrdypu.org/article.asp?issn=0975-2870;year=2016;volume=9;issue=4;spage=430;epage=436;aulast=Garg
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