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How to Read TSH Test Report

TSH Test:

TSH stands for Thyroid Stimulating Hormone, a hormone secreted by the pituitary gland, in high or low amounts, depending upon the requirement. To measure the amount of TSH present in the body, a TSH test is performed. Abnormal TSH levels in the blood indicates inefficient functioning of the thyroid gland.

Factors involved to understand the normal range of TSH levels:

  1. What is the normal range of TSH?
  2. What do high TSH levels mean?
  3. Symptoms that indicate high TSH levels
  4. What do low TSH levels mean?
  5. Symptoms that indicate low TSH levels
  6. Are there any risk factors associated with TSH Test?
  7. What other tests are ordered along with TSH Test?
  8. Precautions to be taken to maintain normal levels of TSH

What is the normal range of TSH?

Normal level of TSH in adults falls in the range of 0.5-5.0 mIU/L.

If a person is already undergoing treatment for a thyroid disorder, then the normal range is between 0.5-3.0 mIU/L. Ranges between laboratories will vary with the upper limit being between 4 to 5.

What do high TSH levels mean?

If the values of TSH obtained during the evaluation are high, it generally indicates an underactive thyroid gland, pointing to hypothyroidism. In this condition, the pituitary gland produces and secretes more TSH to stimulate the thyroid gland into producing more thyroid hormones.

TSH levels may also increase in conditions such as:

  • Acute or Chronic thyroid dysfunction
  • Autoimmune thyroid condition
  • Pituitary tumors resulting in an unregulated production of TSH
  • In a person receiving insufficient thyroid hormone replacement medication after undergoing surgery for thyroid removal

High levels of TSH can be treated by daily doses of medications, such as levothyroxine, that balances the levels of thyroid hormones on an empty stomach half an hour before breakfast, to prevent impairment of absorption by food.

Symptoms that indicate high TSH levels

There are a number of symptoms that indicate TSH levels may be higher than normal. These symptoms vary from patient to patient and depend upon the severity of thyroid hormone deficiency.

Common symptoms include:

  • Fatigue
  • Weakness
  • Dry skin and hair
  • Unexplained weight gain
  • Hair loss
  • Intolerance to cold temperatures
  • Constipation
  • Muscle cramps and aches
  • Depression
  • Irritability
  • Memory Loss
  • Abnormal menstrual cycles

Most people have one of these or a combination of these symptoms. People with hypothyroidism, in certain cases, show no symptoms at all.

What do low TSH levels mean?

Low levels of TSH indicate hyperthyroidism, also known as an overactive thyroid. In this condition, the thyroid gland produces excess amounts of thyroid hormones resulting in a decreased production of TSH from the pituitary gland.

Low levels of TSH can also be due to:

  • Graves disease, an autoimmune condition which is a common cause of hyperthyroidism
  • Excessive intake of thyroid hormone medications by patients with underactive thyroid
  • Damage to the pituitary gland resulting in inadequate production of TSH
  • Treatment for thyroid cancer that uses thyroid hormone suppressors
  • Too much iodine in your body
  • Medications like steroids, dopamine, biotin, could get a lower-than-normal reading

Symptoms that indicate low TSH levels

Symptoms of low TSH levels and their severity depends upon the extent of excess thyroid hormone levels and age of the patient.

Common symptoms experienced by the patients include:

  • Nervousness and irritability
  • Palpitations and increased heart rate
  • Intolerance to heat
  • Tremors
  • Excessive weight loss even with increased appetite
  • Frequent diarrhoea
  • Swelling in lower legs
  • Shortness of breath
  • Decreased menstrual flow
  • Sleep disturbances
  • Vision disturbances
  • Fatigue and muscle weakness
  • Anxiety and restlessness

Are there any risk factors associated with TSH Test?

There is a little risk of slight pain or bruising at the site from where the blood was collected, but it usually fades away on its own. As fasting is required for the test, there may also be a little risk of fainting. However, there are no huge risks associated with a blood test.

What other tests are ordered along with TSH Test?

Abnormal levels of TSH usually indicate thyroid dysfuntion. However, TSH test alone is not sufficient for diagnosis of thyroid disorder and hence, other blood and imaging tests may be advised along with this test. Blood tests may include estimation of free T3 and T4 hormones and antithyroid antibody test.

Imaging tests may include CT scans to check for nodules in the thyroid gland. Nuclear tests such as an Iodine Uptake Test is also recommended to check how well the thyroid is working and the cause of hyperthyroidism. Thyroid Scan Test creates images of the thyroid gland to check for any abnormalities in the size and shape or presence of lumps in the gland.

These tests help in deciding if thyroid treatment is required. A follow-up after 6 weeks is often advised after the start of thyroid hormone replacement medications.

Precautions to be taken to maintain normal levels of TSH

Consuming a healthy and nutritious diet, avoiding processed foods, and taking vitamin D and selenium supplements, are some of the ways to maintain normal thyroid health. Patients with thyroid disorders are advised to take thyroid medications regularly to maintain the levels of TSH.

People with hypothyroidism should focus on consuming meals containing antioxidant rich vegetables such as tomatoes, bell peppers, etc., fruits such as berries, brazil nuts, etc., and lean meat, as they are nutritious, low in calories, and can help prevent weight gain. Iodine is an essential mineral needed to make thyroid hormones. A low iodine diet is generally recommended to patients with hyperthyroidism.

An abnormal TSH level, whether high or low, indicates an excess or deficiency of the amount of thyroid hormones in the body. However, TSH levels alone are not sufficient to diagnose a thyroid disorder and hence, a panel of tests are advised alongside.

Test results are often available 6-8 hours after the test is performed. It is necessary to consult an endocrinologist for the correct interpretation of the results and to determine if treatment is required or not.