Thyrotropin Test

TSH produced by the pituitary. Thyrotropin Test stimulates the release of thyroid hormone from thyroglobulin. It also stimulates the growth of thyroid follicular cells. An abnormal level of TSH Test can mean that the thyroid hormone regulation system is out of whack, usually as a result of a benign condition (Hyperthyroidismor Hypothyroidism).

Also Known as	TSH, Thyrotropin Test, Thyrotropin, Thyroid Stimulating Hormone, Thyrotropic Hormone,
Test Purpose	Diagnose and Monitor the treatment of a Thyroid Disorder
Test Preparations	No Need any Preparation for this Test
Test Components	Thyroid Stimulating Hormone (TSH)
Specimen	2 ML (1 ML Min.) Blood From 1 SST
Stability Room	2 Hours
Stability Refrigerated	48 Hours
Stability Frozen	4 Weeks
Method	Chemiluminescent Immunoassay (CLIA)
Download Report	Download Report

TSH (thyroid stimulating hormone). A Thyrotropin Test is a blood test that measures this hormone. TSH levels that are high or low can be a sign of a thyroid problem.

Why To Get Tested:

The TSH test may be used for the following reasons:

• To diagnose an underactive or overactive thyroid gland
• To detect thyroid disease before it causes symptoms, especially in newborns
• To evaluate a thyroid nodule, which is a lump in the thyroid gland
• To evaluate a goiter, which is an enlarged thyroid gland
• To diagnose or rule out thyroid diseases, such as Hashimoto’s thyroiditis, Graves’ disease, and thyroid cancer
• To monitor a patient’s response to treatment for Hypothyroidism, Hyperthyroidism, or another thyroid condition

When to Get Tested:

If you have symptoms of these disorders, your doctor may order a TSH test or thyroid panel. Symptoms of Hypothyroidism include:

• Fatigue
• Depression
• Weight gain
• I am cold
• Painful joints and muscles
• Dry Skin
• Fine and/or dry hair
• slow heart rate
• Constipation
• irregular menstrual periods
• fertility problems

Symptoms of hyperthyroidism include:

• Weightloss
• Irritability
• Anxiety
• Insomnia
• Difficulty tolerating heat
• Humor changes
• Fast or irregular heartbeat
• Loose and frequent bowel movements

Indications:

• TSH differentiates Hypothyroidismfrom Hyperthyroidism.
• TSH used to diagnose primary Hypothyroidism.
• TSH is used to differentiate primary from secondary Hypothyroidism.
• TSH also differentiates Hypothyroidismdue to the hypothalamus (tertiary Hypothyroidism).
• The TSH level is also done for suppressive or replacement therapy.
• TSH has also been done in a newborn with primary hypothyroidism who has a low T4 level.

Thyroid disorder = T4 decreased + TSH normal or raised
Pituitary disorder = T4 decreased + TSH decreased

Sample Required:

• The serum of a patient is needed.
• 2 ML (1 ML Min.) Blood From 1 SST

Sample Precations:

• Sample with hemolysis or lipemia is rejected.
• Centrifuge the turbid sample before performing the test.

Normal Values:

Source 1

• Male: 0.3 – 5.0 uIU/ml
• Non Pregnant: 0.3 – 5.0 uIU/ml
• Pregnant:
  • First trimester: 0.1 to 2.5 mIU/ml
  • Second trimester: 0.2 to 3.0 mIU/ml
  • Third timester: 0.3 to 3.0 mIU/ml

Source 2:

• Adult = 0.4 to 5.6 mIU/L
• Newborn = 3 to 20 mIU/L
• Cord blood = 3 to 12 µU/mL
  • Values vary between laboratories.

Source 3:

• Adult
• 21 to 54 years = 0.4 to 4.2 mU/L
• 55 to 87 years = 0.5 to 8.9 mU/L
• Newborn = 1.7  to 9.1 mU/L
  • 0.3 to 3.04 mIU/L  (another reference)
• Pregnancy
  • First trimester = 0.3 to 4.5 mU/L
  • Second trimester = 0.5 to 4.6 mU/L
  • Third trimester = 0.8 to 5.2 mU/L

Hyperthyroidism	Normal	Mild hypothyroidism	Hypothyroidism
0.0–0.4 mU/L	0.4–4.0 mU/L	4.0–10.0 mU/L	10.0 mU/L

Thyroid Function Tests Summary:                       

Disease	T3	T4 (total)	T4 free	TSH	Cholesterol
Hypothyroidism,	decreased	decreased	low	increased	increased
Hyperthyroidism	increased	increased	increased	decreased or absent	decreased
Excess Thyroid binding globulin (TBG)	increased	increased	Normal	decreased
Decreased thyroglobulin (TBG)	Low	Low	Normal

TSH	Total and Free T4	Total and Free T3	MOST LIKELY DIAGNOSIS
Normal	Normal	Normal	Normal thyroid function (e.g., “euthyroid”)
Normal or decreased	Normal or decreased	Decreased	Normal adjustment in thyroid function due to illness (nonthyroidal illness or sick euthyroid syndrome)
Increased	Normal	Normal	Subclinical hypothyroidism; in a person with hypothyroidism on treatment, not enough thyroid hormone is being given
Increased	Decreased	Normal of decreased	Hypothyroidism resulting from a problem with the thyroid gland itself (primary hypothyroidism)
Normal or increased	Increased	Increased	Hyperthyroidism resulting from a problem with the pituitary gland signals (central hyperthyroidism) or from a problem with the thyroid hormone receptor (thyroid hormone resistance)
Decreased	Normal	Normal	Subclinical Hyperthyroidism; in a person with Hypothyroidism, too much thyroid hormone is being given
Decreased	Normal	Increased	Hyperthyroidism resulting from the thyroid gland making too much active thyroid hormone T3 (uncommon, also known as T3 toxicosis)
Decreased	Increased	Increased	Hyperthyroidism resulting from the gland making too much thyroid hormones (primary hyperthyroidism)
Decreased	Decreased	Decreased	Hypothyroidism resulting from a problem with the hypothalamus or pituitary signals that govern the thyroid gland (central hypothyroidism)

Increase Level of TSH is seen in

• Hypothyroidism
• Pituitary resistance
• Thyrotropin Releasing Hormone (TRH) Secreting Tumor
• Adults and neonates with primary hypothyroidism.
• Congenital Cretinism.
• Hashimoto’s thyroiditis.
• Thyrotoxicosis due to pituitary tumors.
• TSH antibodies.
• Large doses of iodine.
• Chronic and severe illness.
• Drugs
  • Amiodarone
  • Lithium
  • Haloperidol
  • Chlorpromazine
  • Metoclopramide
  • Metyrapone
  • Domperidone

Decrease Level of TSH is seen in

• Primary Hyperthyroidism.
• Secondary and tertiary Hypothyroidism.
• Overtreatment in a Hypothyroid patient.
• Treated Grave’s disease patient.
• Hyperthyroidism
• Euthyroid Sick Syndrome (associated with acute illness)
• Central Hypothyroidism
  • Hypothyroidism or Pituitary Ademoma causing TSH deficiency and low T4 and T3
• Hyponatremia
• Malnutrition
• Mood Disorders
• Medications
  • Amiodarone
  • Interferon
  • Interleukin-2
  • Opiates
  • Corticosteroids
  • Levothyroxine
  • Levodopa
  • Dopamine Agonists
  • Pyridoxine
  • Bromocriptine
  • Somatostatin analogs
  • Carbemazepine
  • Metformin
  • Biotin (High dose, >5000 mcg/day)

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Possible References Used

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