II. Approach

  1. TSH alone is sufficiently sensitive and specific
    1. TSH is a good single screening outpatient test
    2. Bauer (1996) Arch Intern Med 156:2333-7 [PubMed] (or open in [QxMD Read])

III. Interpretation: Normal Thyroid Stimulating Hormone (TSH): 0.3 to 5.0 mU/L

  1. Euthyroid
  2. No additional testing indicated
  3. Normal Serum TSH range is decreased in pregnancy
    1. See Thyroid Dysfunction in Pregnancy

IV. Interpretation: High Thyroid Stimulating Hormone (TSH): >5-20 mU/L

  1. Normal Free Thyroxine Index or Free T4
    1. Diagnosis: Subclinical Hypothyroidism
    2. Non-specific Symptoms
      1. See Subclinical Hypothyroidism
      2. Consider Levothyroxine
    3. Goiter OR Microsomal Antibodies exceed 1:1600
      1. Positive: Levothyroxine
      2. Negative: Follow clinically
  2. Low Free Thyroxine Index or Free T4
    1. Diagnosis: Hypothyroidism
    2. Management: Levothyroxine

V. Interpretation: Low Thyroid Stimulating Hormone (TSH): <0.3 mU/L

  1. Normal Free Thyroxine Index or Free T4
    1. Normal Triiodothyronine (T3)
      1. Diagnosis: Subclinical Hyperthyroidism
      2. Management
        1. Consider following clinically
        2. Age over 60 years
          1. Risk of Atrial Fibrillation or Osteoporosis
          2. Consider definitive treatment
          3. Observe closely
    2. High Triiodothyronine (T3)
      1. Diagnosis: T3 Toxicosis
      2. Management: Treat Hyperthyroidism
  2. High Free Thyroxine Index or Free T4
    1. Diagnosis: Hyperthyroidism
    2. Radioiodine Uptake scan Elevated:
      1. Grave's Disease
      2. Toxic nodular Goiter
      3. Toxic Thyroid Adenoma
    3. Radioiodine Uptake scan Low or Absent:
      1. Acute viral Thyroiditis
      2. Silent Thyroiditis
      3. Struma ovarii
      4. Excessive Levothyroxine ingestion

Images: Related links to external sites (from Google)

Ontology: Thyroid Function Tests (C0040130)

Concepts Laboratory Procedure (T059)
MSH D013960
SnomedCT 166348009, 143701008, 35650009, 143682007, 166320009
English Function Test, Thyroid, Function Tests, Thyroid, Test, Thyroid Function, Tests, Thyroid Function, Thyroid Function Test, Thyroid Gland Function Tests, thyroid function tests (lab test), thyroid function tests, Thyroid function test (procedure), Thyroid function tests NOS, TFTs, THYROID FUNCTION TEST, THYROID FUNCTION, Test;thyroid function, thyroid panel, tft, Thyroid Function Profiles, Thyroid panel, TFT - Thyroid function test, Thyroid function test, Thyroid panel (procedure), Thyroid function tests, Thyroid Function Tests, thyroid function test
Italian Test di funzionalità tiroidea, Test di funzionalità tiroidea NAS, Prove di funzionalità della tiroide, Prove di funzionalità tiroidea
Dutch TFTs, thyroïdfunctietests NAO, schildklierfunctietest, Onderzoek, schildklierfunctie-, Schildklierfunctietests
French TFT, Explorations fonctionnelles de la thyroïde SAI, Tests d'exploration de la fonction thyroïdienne, Tests de la fonction thyroïdienne, Exploration de la fonction thyroïdienne, Exploration fonctionnelle thyroïdienne, Tests fonctionnels thyroïdiens, Test de la fonction thyroïdienne
German TFTs, Schilddruesenfunktionstests NNB, Schilddruesenfunktionstest, Schilddrüsenfunktionstests
Portuguese Provas funcionais da tiroideia NE, Provas funcionais da tiroideia, Teste da função da tireóide, Testes de Função Tireóidea
Spanish PFT, Pruebas de función tiroidea NEOM, Thyroid function tests, Thyroid function test, grupo de pruebas tiroideas (procedimiento), grupo de pruebas tiroideas, perfil tiroideo, Prueba de función tiroidea, Tests de Funcion de la Tiroides, Tests de Función de la Tiroides, Pruebas de Funcion de la Tiroides, Pruebas de Función de la Tiroides
Japanese 甲状腺機能検査NOS, コウジョウセンキノウケンサ, コウジョウセンキノウケンサNOS, 血漿蛋白結合ヨード試験, 血漿蛋白質結合沃素測定法, 蛋白結合ヨード検査, たんぱく結合ヨード検査, 蛋白質結合沃素試験, 血漿たんぱく結合ヨード測定, 血漿蛋白結合ヨード測定, 血漿蛋白質結合ヨウ素測定法, 血漿たんぱく結合ヨード試験, 甲状腺機能検査
Swedish Sköldkörtelfunktionstester
Czech tyreoidea - funkční testy, Funkční test štítné žlázy, TFT (funkční testy štítné žlázy), Funkční testy štítné žlázy NOS, thyreoidea - funkční testy
Finnish Kilpirauhasen toimintakokeet
Russian BELKOVO-SVIAZANNYI IOD, TEST, SHCHITOVIDNOI ZHELEZY FUNKTSIONAL'NYE TESTY, BELKOVO-SVIAZANNYI IOD, OPREDELENIE, БЕЛКОВО-СВЯЗАННЫЙ ИОД, ОПРЕДЕЛЕНИЕ, БЕЛКОВО-СВЯЗАННЫЙ ИОД, ТЕСТ, ЩИТОВИДНОЙ ЖЕЛЕЗЫ ФУНКЦИОНАЛЬНЫЕ ТЕСТЫ
Croatian TIREOIDEJA, ISPITIVANJA FUNKCIJE
Polish Poziom jodu związanego z białkami, Próby czynnościowe tarczycy
Hungarian Pajzsmirigy funkciós vizsgálat, Pajzsmirigy funkciós vizsgálatok k.m.n., TFT