TSH test measures the level of thyroid-stimulating hormone (TSH) in the blood. TSH, also known as thyrotropin, is produced by the pituitary gland. This hormone plays a crucial role in regulating the thyroid gland. It stimulates the production of thyroid hormones, thyroxine (T4) and triiodothyronine (T3), which play a vital role in regulating metabolism, heart rate and digestion, bone and muscle functioning, and brain development. If the pituitary gland produces too much or too little TSH, it affects how the thyroid gland functions.

A TSH test measures the amount of TSH in the blood and checks for thyroid issues. The TSH test results can indicate whether the thyroid is producing too much or too little hormone. It is typically the first test doctors order if anyone is showing symptoms suggestive of thyroid problems like hyperthyroidism (low levels of TSH) or hypothyroidism (high levels of TSH). It may also be prescribed to track the effectiveness of treatment for thyroid disorders.

If your TSH test results are abnormal, your doctor will likely order additional thyroid blood tests to detect the issue.

The following points need to be considered for a TSH test:

• Prerequisites: Fasting is not needed for the TSH test.

• Best Time to Get Tested: For thyroid testing, it is preferable to provide a morning sample. Additionally, it is important to schedule the test at the same time of day for consistency with each testing session.

• Eligibility for TSH Test: Thyroid problems can affect individuals of any age. Thus, anyone facing symptoms indicating a thyroid issue, is pregnant, facing fertility challenges, or has a family history of thyroid disease can undergo a TSH test. Additionally, a doctor may order this test for people who are taking medications for thyroid disorders (for treatment monitoring purposes).

• Cautions Before Taking TSH Test: Several factors can affect the results of the TSH test, including:

• The time elapsed since the last dose of thyroid medication, especially if it contains T3.

• Stress levels, non-thyroidal illnesses, dietary habits, and sleep patterns.

• Certain medications and supplements one is currently taking.

To ensure precise results and an accurate diagnosis, it is essential to discuss these factors with a doctor before undergoing a TSH test.

TSH testing in Bangalore may be needed if anyone displays symptoms or indications of high or low levels of TSH. Elevated TSH levels typically indicate hypothyroidism, which may manifest as:

• Numbing and tingling sensation in the hands

• Fatigue

• Weight gain (unexplained)

• Depression

• Dry skin or hair

• Sensitivity to cold temperatures

• Constipation

• Decreased libido

• Thinning of hair

• Heavy and frequent menstrual periods

• Pain in joints and muscles

Conversely, low TSH levels usually signify hyperthyroidism, characterised by:

• Sleeping problems

• Feelings of anxiety, shakiness or irritability

• Weight loss (unexplained)

• Weakness in the muscles

• Diarrhoea and frequent bowel movements

• Irregular menstrual cycles

• Irregular or rapid heartbeat

• Changes in vision or protruding eyes

• Warm, thin, and moist skin

• Sensitivity to hot temperatures

• Swelling of the neck due to an enlarged thyroid (goitre)

A doctor may also order this for people who are already managing hypothyroidism or hyperthyroidism to track the progress of their thyroid problem. Furthermore, they might also suggest this test if anyone is considering pregnancy.

Range for TSH Test Results

Below are the typical ranges for healthy individuals who are not pregnant:

• 0.400 to 4.049 µIU/mL

For pregnant individuals, the TSH range is as follows:

Understanding TSH Result Factors

• High Levels

A high TSH level suggests that the thyroid gland is not producing enough thyroid hormone, known as primary hypothyroidism. This could be due to factors such as Hashimoto’s disease, post-pregnancy, inflamed thyroid gland, iodine deficiency or could be present from birth.

• Low Levels

A low TSH level typically indicates an overproduction of thyroid hormone, known as hyperthyroidism. This could be due to factors such as Graves' disease, inflamed thyroid gland, post-pregnancy, thyroid nodules, or excess iodine.

Factors Influencing TSH Results

• Time of Meal and Circadian Rhythm: Few studies have shown that TSH levels can fluctuate depending on food intake and the time of day, with notable variations observed throughout the day and in response to eating.

• Other Factors : It is important to recognise that TSH is a labile hormone and is subject to non-thyroidal pituitary influences (glucocorticoids, somatostatin, dopamine etc.), stress, activity, genetics, poisonous substances and radiation exposure, inflammation of the thyroid gland, deficiency or excess of iodine in the diet, pregnancy, certain medications – antidepressants, cholesterol-lowering drugs, chemotherapy drugs, steroids, thyroid cancer that can disrupt the TSH/free T4 relationship.