Establishment of reference intervals for thyroid function tests during pregnancy

AbstractThyroid function tests are frequently assessed during pregnancy to evaluate thyroid dysfunction or to monitor pre-existing thyroid disease. However, using non-pregnant reference intervals can lead to misclassification. International guidelines recommended that institutions should calculate their own pregnancy-specific reference intervals for free thyroxine (FT4), free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH). The objective of this study is to establish gestation-specific reference intervals (GRIs) for thyroid function tests in pregnant Turkish women and to compare these with the age-matched non-pregnant women.Serum samples were collected from 220 non-pregnant women (age: 18–48), and 2460 pregnant women (age: 18–45) with 945 (39%) in the first trimester, 1120 (45%) in the second trimester, and 395 (16%) in the third trimester. TSH, FT4 and FT3 were measured using the Abbott Architect i2000SR analyzer.GRIs of TSH, FT4 and FT3 for first trimester pregnancies were 0.49–2.33 mIU/L, 10.30–18.11 pmol/L and 3.80–5.81 pmol/L, respectively. GRIs for second trimester pregnancies were 0.51–3.44 mIU/L, 10.30–18.15 pmol/L and 3.69–5.90 pmol/L. GRIs for third trimester pregnancies were 0.58–4.31 mIU/L, 10.30–17.89 pmol/L and 3.67–5.81 pmol/L. GRIs for TSH, FT4 and FT3 were different from non-pregnant normal reference intervals.TSH levels showed an increasing trend from the first trimester to the third trimester, whereas both FT4 and FT3 levels were uniform throughout gestation. GRIs may help in the diagnosis and appropriate management of thyroid dysfunction during pregnancy which will prevent both maternal and fetal complications.

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Reference Intervals of Thyroid Function Tests in First Trimester Vietnamese Pregnant Women

Clinical Laboratory ◽

10.7754/clin.lab.2020.200415 ◽

2020 ◽

Vol 66 (12/2020) ◽

Author(s):

Luong Ly ◽

Nhu Vuong ◽

Minh Chau ◽

Hanh Phan ◽

Quan Pham ◽

...

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

First Trimester ◽

Reference Intervals ◽

Thyroid Function Tests ◽

Function Tests

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A study to establish gestation-specific reference intervals for thyroid function tests in normal singleton pregnancy

Yearbook of Pathology and Laboratory Medicine ◽

10.1016/s1077-9108(08)79068-6 ◽

2009 ◽

Vol 2009 ◽

pp. 245

Author(s):

M.G. Bissell

Keyword(s):

Thyroid Function ◽

Reference Intervals ◽

Specific Reference ◽

Thyroid Function Tests ◽

Singleton Pregnancy ◽

Function Tests

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Establishment of reference intervals of thyroid function tests from cord blood of neonates in two selected hospitals, Addis Ababa, Ethiopia

BMC Pediatrics ◽

10.1186/s12887-016-0654-2 ◽

2016 ◽

Vol 16 (1) ◽

Cited By ~ 3

Author(s):

Aman Mehari ◽

Feyssa Challa ◽

Goitom Gebreyesus ◽

Dereje Alemayehu ◽

Daniel Seifu

Keyword(s):

Cord Blood ◽

Thyroid Function ◽

Addis Ababa ◽

Reference Intervals ◽

Thyroid Function Tests ◽

Function Tests

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Trimester-specific reference intervals of thyroid function tests in Turkish pregnants

Gynecological Endocrinology ◽

10.1080/09513590.2019.1666817 ◽

2019 ◽

Vol 36 (5) ◽

pp. 413-416

Author(s):

Oktay Bulur ◽

Zeliha Atak ◽

Derun Taner Ertugrul ◽

Esin Beyan ◽

Emre Gunakan ◽

...

Keyword(s):

Thyroid Function ◽

Reference Intervals ◽

Specific Reference ◽

Thyroid Function Tests ◽

Function Tests

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A study to establish gestation-specific reference intervals for thyroid function tests in normal singleton pregnancy

European Journal of Obstetrics & Gynecology and Reproductive Biology ◽

10.1016/j.ejogrb.2007.10.007 ◽

2008 ◽

Vol 137 (1) ◽

pp. 61-66 ◽

Cited By ~ 33

Author(s):

Christina Cotzias ◽

Sarah-Jane Wong ◽

Erica Taylor ◽

Paul Seed ◽

Joanna Girling

Keyword(s):

Thyroid Function ◽

Reference Intervals ◽

Specific Reference ◽

Thyroid Function Tests ◽

Singleton Pregnancy ◽

Function Tests

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First- and Second-Trimester Reference Intervals for Thyroid Function Testing in a US Population

American Journal of Clinical Pathology ◽

10.1093/ajcp/aqaa165 ◽

2020 ◽

Author(s):

Dustin R Bunch ◽

Kyle Firmender ◽

Roa Harb ◽

Joe M El-Khoury

Keyword(s):

Thyroid Function ◽

The United States ◽

Reference Intervals ◽

Adverse Outcomes ◽

Specific Reference ◽

Thyroid Peroxidase ◽

Thyroid Function Tests ◽

Second Trimester ◽

Function Tests ◽

Increased Risk

Abstract Objectives Thyroid dysfunction in pregnancy is associated with increased risk of adverse outcomes to mother and child. Trimester-specific reference intervals for thyroid function tests are not routinely provided by clinical laboratories. In this study, we present first- and second-trimester-specific reference intervals in a US population for thyroid-stimulating hormone (TSH), free thyroxine (FT4), total thyroxine (T4), and total triiodothyronine (T3) measured on Roche analyzers. Methods We used patient samples from first- and second-trimester prenatal screening. Samples were limited to singleton pregnancies and negative screening results for thyroid peroxidase and thyroglobulin antibodies. Analytes (TSH, FT4, T4, and T3) were measured on a Roche Modular e170 then verified on a Roche cobas e801. Results The reference intervals established on the e170 and verified on the e801 for the first trimester were 0.11 to 3.48 mIU/L for TSH, 11.2 to 19.0 pmol/L for FT4, 51.1 to 185.6 nmol/L for T4, and 1.4 to 3.5 nmol/L for T3. The reference intervals for the second trimester were 0.31 to 3.85 mIU/L for TSH, 9.4 to 16.5 pmol/L for FT4, 55.1 to 174.0 nmol/L for T4, and 1.5 to 3.7 nmol/L for T3. Conclusions This is the first report of trimester-specific reference intervals for thyroid function tests on Roche analyzers in the United States, and it is consistent with worldwide reports.

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