Download App iOS Android

TSH

About the test
What is this test done for?
The test evaluates levels of the thyroid stimulating hormone (TSH) of the blood. TSH is produced by a small gland called pituitary, located at the base of the brain.
Why is it Done?

The test is carried out to:

  • Rule out hypothyroidism
  • Rule out hyperthyroidism

TSH levels help in confirming the diagnosis of hypothyroidism as well as hyperthyroidism and in assessing their severity. TSH is done singularly as a basic screening test for thyroid function. TSH test, along with other tests of the thyroid panel / thyroid profile, helps in accurate diagnosis of underlying thyroid or pituitary disease.

When should it be performed?

This test is performed when a person has:

  • Symptoms of hypothyroidism such as:
    • Obesity
    • Easy fatigability
    • Constipation
    • Increased sensitivity to cold
    • Weight gain
    • Puffy face, especially in the morning
    • Dry skin
    • Muscle weakness
    • Pain, stiffness and swelling of joints
    • Irregular menstrual periods
    • Thinning of hair
    • High levels of cholesterol in blood
    • Slow heart rate
    • Impaired memory or depression.
  • Symptoms of hyperthyroidism such as:
    • Sudden weight loss
    • Increased appetite
    • Rapid heart beat
    • Tremors (fine trembling of hands and fingers)
    • Increased sweating (hyperhidrosis)
    • Increased bowel frequency
    • Increased sensitivity to heat
    • Changes in menstrual pattern
    • Nervousness, anxiety and irritability
    • Fatigue and muscle weakness
    • Thin and brittle hair.
  • In patients of existing thyroid disorder, the test is done regularly to monitor the course of treatment.
  • History of post-partum thyroiditis
  • Those undergoing radiation therapy for cancer of head, face, or neck
  • Rheumatoid arthritis patients undergoing treatment with amiodarone or lithium, then 6-12 months during treatment and 12 months after the treatment
How is it done
A blood sample will be collected from a vein in your arm. No special preparations like fasting required.
Results

The test result is normal if TSH levels are 0.5-5.0 mU/L.

It means either of the following:

  • Absence of any thyroid disease (called euthyroidism)
  • Adequate thyroxine dose for treating hypothyroidism
  • Adequate therapy of hyperthyroidism.

If TSH levels are above 10 mU/L (high); and corresponding free T4 levels are below 5.0 pmol/L (low), it indicates either of the following:

  • Hypothyroidism
  • Poorly controlled hypothyroidism, or
  • Over controlled hyperthyroidism

If TSH levels are below 0.5 mU/L (low); and corresponding free T4 levels are above 25.0 pmol/L (high), it indicates either of the following:

  • Hyperthyroidism
  • Poorly controlled hyperthyroidism
  • Over controlled hypothyroidism

If TSH levels are between  5 - 10 mU/L and Free T4 levels are 9.0-25.0 pmol/L; it means subclinical hypothyroidism. i.e. no symptoms

If TSH levels are below 0.5 mU/L (low) and Free T4 levels are below 9 pmol/L (low); it means either of the following:

  • Hypopituitarism
  • Secondary hypothyroidism
  • Response to a significant non-thyroid illness

If Free T3 levels are above 8 pmol/L (high), it means hyperthyroidism. If Free T3 levels are very high, it means severe form of hyperthyroidism.

Other Tests

Other tests that can be done after TSH is tested include:

  • Thyroid panel test/ Thyroid profile: which has T3, T4, free T3, and free T4 along with TSH.
  • Anti TPO antibodies
    • Presence of Anti TPO antibodies suggest the cause of hypothyroidism as autoimmune thyroiditis
  • TRAb (TSH receptor antibodies)
    • This is a specific test for ruling out Grave’s disease
  • Thyroglobulin antibodies
    • This test is done for checking antibodies against thyroglobulin
    • It indicates the cause of thyroid disease as Hashimoto’s thyroiditis or idiopathic myxedema.
100%
Trusted Labs
Upto 75%
off on diagnostic tests
Free sample pickup