Last updated January 18, 2022

Hypothyroidism in Adults

RECOMMENDATIONS

Anti-thyroid peroxidase antibody (TPOAb) measurements should be considered when evaluating patients with subclinical hypothyroidism. (I, B)
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TPOAb measurement should be considered in order to identify autoimmune thyroiditis when nodular thyroid disease is suspected to be due to autoimmune thyroid disease. (IV, D)
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TPOAb measurement should be considered when evaluating patients with recurrent miscarriage, with or without infertility. (II, A)
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Measurement of TSHRAbs using a sensitive assay should be considered in hypothyroid pregnant patients with a history of Graves’ disease who were treated with radioactive iodine or thyroidectomy prior to pregnancy. This should be initially done either at 20-26 weeks of gestation or during the first trimester and if they are elevated again at 20-26 weeks of gestation. (II, A)
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Clinical scoring systems should not be used to diagnose hypothyroidism. (I, A)
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Tests such as clinical assessment of reflex relaxation time, cholesterol, and muscle enzymes should not be used to diagnose hypothyroidism. (II, B)
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Apart from pregnancy, assessment of serum free T4 should be done instead of total T4 in the evaluation of hypothyroidism. An assessment of serum free T4 includes a free T4 index or free T4 estimate and direct immunoassay of free T4 without physical separation using anti-T4 antibody. (I, A)
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Assessment of serum free T4, in addition to TSH, should be considered when monitoring L-thyroxine therapy. (I, B)
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In pregnancy, the measurement of total T4 or a free T4 index, in addition to TSH, should be done to assess thyroid status. Because of the wide variation in the results of different free T4 assays, direct immunoassay measurement of free T4 should only be employed when method-specific and trimester-specific reference ranges for serum free T4 are available. (II, B)
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Serum total T3 or assessment of serum free T3 should not be done to diagnose hypothyroidism. (II, A)
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TSH measurements in hospitalized patients should be done only if there is an index of suspicion for thyroid dysfunction. (II, A)
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In patients with central hypothyroidism, assessment of free T4 or free T4 index, not TSH, should be done to diagnose and guide treatment of hypothyroidism. (I, A)
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Patients being treated for established hypothyroidism should have serum TSH measurements done at 4-8 weeks after initiating treatment or after a change in dose. Once an adequate replacement dose has been determined, periodic TSH measurements should be done after 6 months and then at 12-month intervals, or more frequently if the clinical situation dictates otherwise. (II, B)
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The reference range of a given laboratory should determine the upper limit of normal for a third generation TSH assay. The normal TSH reference range changes with age. If an age-based upper limit of normal for a third generation TSH assay is not available in an iodine sufficient area, an upper limit of normal of 4.12 should be considered. (I, A)
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In pregnancy, the upper limit of the normal range should be based on trimester-specific ranges for that laboratory. If trimester-specific reference ranges for TSH are not available in the laboratory, the following upper normal reference ranges are recommended: first trimester, 2.5 mIU/L; second trimester, 3.0 mIU/L; third trimester, 3.5 mIU/L. (II, B)
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Patients whose serum TSH levels exceed 10 mIU/L are at increased risk for heart failure and cardiovascular mortality, and should be considered for treatment with L-thyroxine. (I, B)
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Treatment based on individual factors for patients with TSH levels between the upper limit of a given laboratory’s reference range and 10 mIU/L should be considered particularly if patients have symptoms suggestive of hypothyroidism, positive TPOAb or evidence of atherosclerotic cardiovascular disease, heart failure, or associated risk factors for these diseases. (I, B)
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In patients with hypothyroidism who are not pregnant, the target range should be the normal range of a third generation TSH assay. If an upper limit of normal for a third generation TSH assay is not available, in iodine-sufficient areas an upper limit of normal of 4.12 mIU/L should be considered and if a lower limit of normal is not available, 0.45 mIU/L should be considered. (II, B)
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In patients with hypothyroidism who are pregnant, the target range for TSH should be based on trimester-specific ranges for that laboratory. If trimester-specific reference ranges are not available in the laboratory, the following upper-normal reference ranges are recommended: first trimester, 2.5 mIU/L; second trimester, 3.0 mIU/L; and third trimester, 3.5 mIU/L. (II, C)
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Treatment with L-thyroxine should be considered in women of childbearing age with serum TSH levels between 2.5 mIU/L and the upper limit of normal for a given laboratory’s reference range if they are in the first trimester of pregnancy or planning a pregnancy including assisted reproduction in the immediate future. Treatment with L-thyroxine should be considered in women in the second trimester of pregnancy with serum TSH levels between 3.0 mIU/L and the upper limit of normal for a given laboratory’s reference range and in women in the third trimester of pregnancy with serum TSH levels between 3.5 mIU/L and the upper limit of normal for a given laboratory’s reference range. (II, B)
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Treatment with L-thyroxine should be considered in women of childbearing age with normal serum TSH levels when they are pregnant or planning a pregnancy, including assisted reproduction in the immediate future, if they have or have had positive levels of serum TPOAb, particularly when there is a history of miscarriage or past history of hypothyroidism. (II, B)
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Women of childbearing age who are pregnant or planning a pregnancy, including assisted reproduction in the immediate future, should be treated with L-thyroxine if they have or have had positive levels of serum TPOAb and their TSH is greater than 2.5 mIU/L. (II, B)
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Women with positive levels of serum TPOAb or with a TSH greater than 2.5 mIU/L who are not being treated with L-thyroxine should be monitored every 4 weeks in the first 20 weeks of pregnancy for the development of hypothyroidism. (II, B)
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Universal screening is not recommended for patients who are pregnant or are planning pregnancy, including assisted reproduction. (I, B)
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“Aggressive case finding,” rather than universal screening, should be considered for patients who are planning pregnancy. (II, C)
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Screening for hypothyroidism should be considered in patients over the age of 60. (I, B)
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“Aggressive case finding” should be considered in those at increased risk for hypothyroidism. (II, B)
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Patients with hypothyroidism should be treated with L-thyroxine monotherapy. (I, A)
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The evidence does not support using L-thyroxine and L-triiodothyronine combinations to treat hypothyroidism. (I, B)
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L-thyroxine and L-triiodothyronine combinations should not be administered to pregnant women or those planning pregnancy. (III, B)
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There is no evidence to support using desiccated thyroid hormone in preference to L-thyroxine monotherapy in the treatment of hypothyroidism and therefore desiccated thyroid hormone should not be used for the treatment of hypothyroidism. (IV, D)
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3,5,3´-triiodothyroacetic acid (TRIAC; tiratricol) should not be used to treat primary and central hypothyroidism due to suggestions of harm in the literature. (III, C)
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Patients resuming L-thyroxine therapy after interruption (less than 6 weeks) and without an intercurrent cardiac event or marked weight loss may resume their previously employed full replacement doses. (IV, D)
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When initiating therapy in young healthy adults with overt hypothyroidism, beginning treatment with full replacement doses should be considered. (II, B)
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When initiating therapy in patients older than 50-60 years with over hypothyroidism, without evidence of coronary heart disease, an L-thyroxine dose of 50 μg daily should be considered. (IV, D)
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In patients with subclinical hypothyroidism initial L-thyroxine dosing is generally lower than what is required in the treatment of overt hypothyroidism. A daily dose of 25 to 75 μg should be considered, depending on the degree of TSH elevation. Further adjustments should be guided by clinical response and follow up laboratory determinations including TSH values. (II, B)
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Treatment with glucocorticoids in patients with combined adrenal insufficiency and hypothyroidism should precede treatment with L-thyroxine. (II, B)
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L-thyroxine should be taken with water consistently 30-60 minutes before breakfast or at bedtime 4 hours after the last meal. It should be stored properly per product insert and not taken with substances or medications that interfere with its absorption. (II, B)
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In patients with central hypothyroidism, assessments of serum free T4 should guide therapy and targeted to exceed the midnormal range value for the assay being used. (III, B)
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In patients with hypothyroidism being treated with L-thyroxine who are pregnant, serum TSH should be promptly measured after conception and L-thyroxine dosage adjusted, with a goal TSH of less than 2.5 mIU/L during the first trimester. (II, B)
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In patients with hypothyroidism being treated with L-thyroxine who are pregnant, the goal TSH during the second trimester should be less than 3 mIU/L and during the third trimester should be less than 3.5 mIU/L. (II, C)
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Maternal serum TSH (and total T4) should be monitored every 4 weeks during the first half of pregnancy and at least once between 26 and 32 weeks gestation and L-thyroxine dosages adjusted as indicated. (II, B)
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In patients receiving L-thyroxine treatment for hypothyroidism, serum TSH should be remeasured within 4-8 weeks of initiation of treatment with drugs that decrease the bioavailability or alter the metabolic disposition of the L-thyroxine dose. (I, A)
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Apart from pregnant patients being treated with L-thyroxine for hypothyroidism, the evidence does not support targeting specific TSH values within the normal reference range. (II, B)
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Physicians who are not endocrinologists, but who are familiar with the diagnosis and treatment of hypothyroidism should be able to care for most patients with primary hypothyroidism. However, patients with hypothyroidism who fall into the following categories should be seen in consultation with an endocrinologist. These categories are (i) children and infants, (ii) patients in whom it is difficult to render and maintain a euthyroid state, (iii) pregnancy, (iv) women planning conception, (v) cardiac disease, (vi) presence of goiter, nodule, or other structural changes in the thyroid gland, (vii) presence of other endocrine disease such as adrenal and pituitary disorders, (viii) unusual constellation of thyroid function test results and (ix) unusual causes of hypothyroidism such as those induced by agents that interfere with absorption of L-thyroxine impact thyroid gland hormone production or secretion, affect the hypothalamic-pituitary-thyroid axis (directly or indirectly), increase clearance, or peripherally impact metabolism. (III, C)
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Thyroid hormones should not be used to treat symptoms suggestive of hypothyroidism without biochemical confirmation of the diagnosis. (II, B)
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Thyroid hormones should not be used to treat obesity in euthyroid patients. (II, A)
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There is insufficient evidence to support using thyroid hormones to treat depression in euthyroid patients. (II, B)
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Iodine supplementation, including kelp or other iodine-containing functional foods, should not be used in the management of hypothyroidism in iodine-sufficient areas. (III, C)
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Iodine supplementation in the form of kelp or other seaweed-based products should not be used to treat iodine deficiency in pregnant women. (IV, D)
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Selenium should not be used to prevent or treat hypothyroidism. (II, B)
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Patients taking dietary supplements and nutraceuticals for hypothyroidism should be advised that commercially available thyroid-enhancing products are not a remedy for hypothyroidism and should be counseled about the potential side effects of various preparations particularly those containing iodine or sympathomimetic amines as well as those marked as “thyroid support” since they could be adulterated with L-thyroxine or L-triiodothyronine. (IV, D)
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Recommendation Grading

Overview

Title

Hypothyroidism in Adults

Authoring Organizations

Publication Month/Year

December 1, 2013

Document Type

Guideline

External Publication Status

Published

Country of Publication

US

Inclusion Criteria

Female, Male, Adult, Older adult

Health Care Settings

Ambulatory

Scope

Diagnosis, Management, Treatment

Diseases/Conditions (MeSH)

D007037 - Hypothyroidism

Keywords

hypothyroidism, thyroid stimulating hormone (TSH)

Source Citation

Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, Pessah-Pollack R, Singer PA, Woeber KA; American Association of Clinical Endocrinologists and American Thyroid Association Taskforce on Hypothyroidism in Adults. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract. 2012 Nov-Dec;18(6):988-1028. doi: 10.4158/EP12280.GL. Erratum in: Endocr Pract. 2013 Jan-Feb;19(1):175. PMID: 23246686.