II. Physiology

  1. See Thyroid Physiology
  2. Variation
    1. TSH levels follow a circadian rhythm
      1. TSH will vary as much as 1-2 uIU/ml over the course of the day
      2. Consider drawing TSH at the same time of day for longterm serial measurements
    2. TSH levels increase with normal aging in euthyroid patients
      1. Consider using age-adjusted TSH interpretation
      2. Age 20-29: 3.56 mIU/ml is 97th percentile
      3. Age >80: 7.49 mIU/ml is 97th percentile
      4. Surks (2007) JCEM 92: 4575
    3. Pregnancy
      1. See Thyroid Dysfunction in Pregnancy
      2. See Hypothyroidism in Pregnancy
      3. Maintaining euthyroid state in pregnancy is critical
    4. Euthyroid individuals still have considerable variation in TSH levels over time
    5. Populations of euthyroid individuals also have considerable variation in TSH levels
  3. Regulation
    1. Negative feedback
      1. Unbound Thyroxine (Free T4)
      2. Unbound Triiodothyronine (Free T3)
    2. Positive Stimulation
      1. Thyroid Releasing Hormone (TRH)

III. Interpretation: Non-Pregnant

  1. Normal
    1. Random: 0.3 - 5.0 uIU/ml
    2. Following Thyroid Releasing Hormone (TRH) stimulation
      1. TSH: 9-30 uIU/ml at 20-30 min
  2. Borderline Increased: 5-10 uIU/ml
  3. High: >10 uIU/ml

IV. Interpretation: Pregnancy

  1. Non-pregnanct: 0.3 to 4.3 mIU/ml
  2. First trimester: 0.1 to 2.5 mIU/ml
  3. Second trimester: 0.2 to 3.0 mIU/ml
  4. Third timester: 0.3 to 3.0 mIU/ml
  5. Abbassi (2010) Obstet Gynecol 114(6): 1326-31

V. Causes: Increased TSH

  1. Hypothyroidism
  2. Drugs
    1. Haloperidol
    2. Chlorpromazine
    3. Metoclopramide
    4. Domperidone
  3. TSH antibodies
  4. Pituitary resistance

VI. Causes: Decreased TSH

  1. Hyperthyroidism
  2. Euthyroid Sick Syndrome (associated with acute illness)
  3. Pituitary disease causing TSH deficiency
  4. Hyponatremia
  5. Malnutrition
  6. Mood Disorders
  7. Medications
    1. Opiates
    2. Corticosteroids
    3. Levodopa
    4. Dopamine
    5. Pyridoxine
    6. Bromocriptine

Images: Related links to external sites (from Google)

Ontology: Thyrotropin (C0040160)

Definition (MSH) A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.
Definition (NCI) A peptide hormone secreted by the anterior pituitary. It promotes the growth of the thyroid gland and stimulates the synthesis of thyroid hormones and the release of thyroxine by the thyroid gland.
Definition (CSP) glycoprotein hormone of the anterior pituitary that promotes the growth of, sustains, and stimulates hormonal secretion of the thyroid gland.
Definition (NCI) A hormone produced by the pituitary gland. TSH stimulates the release of thyroid hormone from thyroglobulin. It also stimulates the growth of thyroid follicular cells. An abnormal TSH level may mean that the thyroid hormonal regulation system is out of control, usually as a result of a benign condition (hyperthyroidism or hypothyroidism).
Concepts Amino Acid, Peptide, or Protein (T116) , Pharmacologic Substance(T121) , Hormone(T125)
MSH D013972
SnomedCT 65428006, 326013007, 24096000
English Thyroid stimulating hormone (TSH), Hormone, Thyroid-Stimulating, Thyreotropin, Thyroid-Stimulating Hormone, Thyrotrophin, Thyrotropin, thyrotropin, TSH preparation, Thyrotrophic hormone product, Thyrotropic hormone preparation, thyroid-stimulating hormone, TSH - Thyroid stimulating hormone, TSH-Thyroid stim horm, Thyroid Stimulating Hormone [EPC], Thyrotropin [Chemical/Ingredient], Thyroid Stimulating Hormone, thyroid stimulating hormone (TSH), thyrotropic hormone, thyroid stimulating hormone, TSH (Thyroid Stimulating Hormone), TSH, Thyroid stimulating hormone, Thyrotrophin product, Thyroid stimulating hormone (substance), Thyrotrophin product (product), Thyrotrophin product (substance), Thyrotropic hormone preparation (product), Thyrotropic hormone preparation (substance), Thyrotropic Hormone
Portuguese Hormônio Tireoestimulante, Tirotropina, Tireotropina, Tireotrofina, Hormônio Estimulante da Glândula Tireóide, Hormônio Estimulante da Tireóide, Tirotrofina
Swedish Tyreotropin
Czech tyreoideu stimulující hormon, TSH, tyreotropin, thyreotropin
Finnish Tyreotropiini
French TSH (Thyroid-stimulating hormone), Thyréotrophine, Thyréostimuline, Thyréotropine, Thyrotropine, Thyrotrophine, Hormone thyréotrope
Russian TIREOTROPNYI GORMON, SHCHITOVIDNUIU ZHELEZU STIMULIRUIUSHCHII GORMON, TIROTROPIN, SHCHITOVIDNOI ZHELEZY STIMULIRUIUSHCHII GORMON, TIREOSTIMULIRUIUSHCHII GIPOFIZARNYI GORMON, TIREOTROPIN, TSH, ТИРЕОСТИМУЛИРУЮЩИЙ ГИПОФИЗАРНЫЙ ГОРМОН, ТИРЕОТРОПИН, ТИРЕОТРОПНЫЙ ГОРМОН, ТИРОТРОПИН, ЩИТОВИДНОЙ ЖЕЛЕЗЫ СТИМУЛИРУЮЩИЙ ГОРМОН, ЩИТОВИДНУЮ ЖЕЛЕЗУ СТИМУЛИРУЮЩИЙ ГОРМОН
Japanese 甲状腺刺激ホルモン, チトロパール, チロトロピン, サイロトロピン
Spanish tirotrofina, producto (producto), tirotrofina (producto), tirotrofina, producto, hormona estimulante tiroidea, hormona tiroideoestimulante, preparado de TSH, preparado de hormona tirotrófica (producto), preparado de hormona tirotrófica (sustancia), preparado de hormona tirotrófica, preparado de hormona tirotrópica, preparado de tirotrofina, tirotrofina (sustancia), tirotrofina, tirotropina, Tirotropina, Hormona Estimulante de la Tiroides
Italian Tireotropina, TSH (Ormone stimolante la tiroide), Ormone stimolante la tiroide, Tirotropina
Croatian TIREOTROPIN, TIROTROPIN
Polish Tyreotropina, Hormon tyreotropowy, TSH
German Thyreoidea-stimulierendes Hormon, Thyreotropin, TSH (Thyreoidea-stimulierendes Hormon)