The thyroid gland, which is butterfly-shaped and situated at the lower region of the neck, is responsible for regulating body weight, temperature and muscle strength, along with your mood.

TSH in the blood stands for Thyroid Stimulating Hormone and is a marker test to diagnose the functioning of the thyroid gland.  TSH is a hormone produced and secreted into the bloodstream by the pituitary gland situated in the brain. TSH binds to the receptor cells present in the thyroid gland that secretes the thyroid hormone.

Thyroid hormones monitor the energy usage by the body, thereby regulating metabolism. Metabolism is described as the process of food being converted into energy and is measured as BMR or Basal Metabolism Rate. The value of BMR is directly influenced by the thyroid hormone.

Altered functioning of the thyroid gland is signified by disturbed metabolism, which further leads to other health consequences.  Poor functioning of the thyroid gland may present with symptoms such as hair loss, dry skin, mood swings, depression, menstrual irregularities, cold extremities, perfused sweating and stunted growth in children.

The TSH test acts as an ‘early warning signal’ in diagnosing and managing the conditions beforehand. This test can be taken by anyone as a part of a routine health checkup or when advised by a doctor.

The Thyroid Stimulating Hormone (TSH) test is also prescribed if a noticeable lump develops near the lower neck or throat region due to the enlargement of the thyroid gland, a condition commonly known as Goitre. A person diagnosed with Goitre may have hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid) as a result of TSH test.

If your thyroid gland is functioning well, then the TSH level will be within the normal range. If the levels of TSH are on the higher or lower side, then the thyroid gland is not working optimally. Low thyroid levels (T3, T4) in the blood mean the pituitary gland is producing and releasing more TSH. In contrast, a high thyroid level signifies the pituitary gland is forming low levels of TSH. Both scenarios state abnormal functioning of the thyroid gland.

The value range of TSH tests varies in children, during pregnancy and with the region of residence. It is an important test during and before pregnancy, as abnormal thyroid function can affect the growth of the foetus.

Thyroid disorders are endemic to certain parts of India where the naturally available iodine is poor.  Also, women are more likely to be diagnosed with thyroid disorders compared to men. Individuals are more likely to suffer from thyroid disorders with less iodine intake in the diet, certain environmental factors and lifestyle.

Other Names of TSH Test

• Thyrotropic hormone
• Thyroid Stimulating Hormone
• TSH

What does the TSH test detect/measure and who is this prescribed for?

The TSH test is the first-line diagnosis to measure the functioning of the thyroid gland.

A person may experience the following symptoms if their thyroid gland is not functioning properly:

• Unexplained weight loss
• Lack of energy
• Constipation or diarrhoea
• Feeling too cold or too hot
• Not able to put on weight with a healthy diet
• Hair fall, thinning of hair, easy breaking of hair
• Swelling in the throat
• Lassitude, lack of energy
• Cramps in the wrist and legs
• Increase in weight
• Anxiety, mood swings
• Fast heartbeat

Some diseases/conditions for which a TSH test can be prescribed are:

• Goitre
• PCOS (and other menstrual irregularities)
• During pregnancy
• Obesity
• Hereditary history of thyroid disorders
• Autoimmune disorders (Hashimoto's thyroiditis)

Following the diagnosis and the test results of TSH, the physician or endocrinologist will suggest and start with a treatment plan depending on the result of TSH test, if required. After initiating the treatment with the appropriate medication, the doctor may prescribe a TSH test after a certain period to monitor the effectiveness of the treatment and for dosage modification, if any.

Some medications like vitamin supplements and biotin may alter the result of the TSH test. It is necessary to provide a complete detailed history before undergoing a test procedure.

The TSH blood test is applicable for males and females, both adults and children.

The TSH test result is based on the analysis of a blood sample collected through the vein via a small needle.

Test Preparation

Before the test

The procedure for the TSH test is not intense. However, inform your doctor about all the medications you are on currently. Also, avoid the intake of medications like biotin, Vitamin B7 and multivitamins.

During the test

A phlebotomist (a person trained to draw blood samples) will collect your blood sample from the vein of the upper arm. You might feel the slight needle-prick. TSH testing for newborn babies is done by collecting blood samples from the heel region.

This entire process is hassle-free and time-saving and takes less than 3 minutes.

After the test

When done hygienically and according to protocol, the TSH test procedure poses no serious threats to an individual. There might be slight soreness due to needle insertion and lightheadedness.

What does the TSH test detect/measure and who is this prescribed for?

The TSH test is the first-line diagnosis to measure the functioning of the thyroid gland.

A person may experience the following symptoms if their thyroid gland is not functioning properly:

• Unexplained weight loss
• Lack of energy
• Constipation or diarrhoea
• Feeling too cold or too hot
• Not able to put on weight with a healthy diet
• Hair fall, thinning of hair, easy breaking of hair
• Swelling in the throat
• Lassitude, lack of energy
• Cramps in the wrist and legs
• Increase in weight
• Anxiety, mood swings
• Fast heartbeat

Some diseases/conditions for which a TSH test can be prescribed are:

• Goitre
• PCOS (and other menstrual irregularities)
• During pregnancy
• Obesity
• Hereditary history of thyroid disorders
• Autoimmune disorders (Hashimoto's thyroiditis)

Following the diagnosis and the test results of TSH, the physician or endocrinologist will suggest and start with a treatment plan depending on the result of the TSH test if required. After initiating the treatment with the appropriate medication, the doctor may prescribe a TSH test after a certain period to monitor the effectiveness of the treatment and for dosage modification, if any.

Some medications like vitamin supplements and biotin may alter the result of the TSH test. It is necessary to provide a complete detailed history before undergoing a test procedure.

The TSH blood test is applicable for males and females, both adults and children.

Hyperthyroidism, Hypothyroidism, Grave’s disease, Hashimoto’s thyroiditis

TSH levels vary during each trimester of pregnancy and should be interpreted and managed by a doctor.

TSH levels are higher during birth and slowly decrease with age.

There may be a minimal difference in the normal values of TSH between males and females, but the range remains constant.

The normal values, parameters, and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

If the TSH value is higher than the normal range, it means the thyroid gland is not functioning optimally. This diagnostic interpretation of the TSH test in this scenario is known as hypothyroidism.

If the TSH value is on the lower side or lower than normal, it means the thyroid gland is working overtime. This reading means the BMR (Body Metabolism Rate) would be higher than normal. Thus, the body consumes more calories and more energy is created. This phenomenon could be a sign of hyperthyroidism, Grave’s disease or Hashimoto’s Thyroiditis.

Certain factors to be considered while interpreting the results are:

• Age: Elderly people are more likely to have high TSH levels indicating hypothyroidism.
• Pregnancy: A lot of hormonal changes take place during pregnancy. Thus, during the first trimester, the TSH level may be low and will gradually increase.
• Illness: Certain severe disease conditions may alter the thyroid hormone levels resulting in low TSH levels.