The TSH Test – What You Should Know


TSH stands for thyroid stimulating hormone and the TSH test helps measure the level of this hormone in your blood. TSH is produced by the pituitary gland in the brain. The pituitary gland, in turn, conveys the message to the thyroid to make and release the thyroid hormones into the bloodstream. The hormones produced by the thyroid gland help regulate the body's metabolic rate, the body’s heart and digestive functions, brain development, muscle control and bone maintenance. Any imbalances in the production of this hormone can show up in the form of various symptoms. Based on these symptoms, your physician may recommend the TSH test, in some cases along with others like Free T3 and Free T4. For your part, here are a few things that can help you stay savvy about the test and what it entails.

Preparing for the test

TSH is a simple test that requires your blood sample and does not require overnight fasting. However, it’s recommended to take the test in the morning as TSH levels fluctuate through the day.The only other thing to keep in mind is to check with your physician if you are on medication for any other condition. For instance, you may have to come off drugs like lithium and dopamine before the test.

What do low or high levels of TSH indicate?

The normal range for TSH is anywhere between 0.4 - 5 mIU/L (milli-international units per litre). If the test reveals lower than normal levels of TSH, it could mean an overactive thyroid. The causes for it could be, but not necessarily restricted to:

  • Excessive iodine in the body
  • Excessive thyroid hormone medication
  • An excessive intake of a natural supplement that could contain the hormone
  • Medications like steroids, dopamine, or morphine could also trigger the reading
  • Graves’ disease – a condition where the body’s immune system attacks the thyroid

If the TSH level is higher than the ideal range, it could be an indication of an underactive gland.

Thyroid and Pregnancy

Pregnancy is also known to affect TSH levels. During pregnancy, the size of the gland increases by 10% or more. Further, the production of T3 and T4 thyroid hormones also increase by around 50%. Consequently, the normal TSH level during pregnancy can be lower than normal.Laboratories establish their own trimester-specific reference ranges for TSH levels. The widely recognised range for TSH levels during pregnancy is:

  • First trimester: 0.1-2.5 mIU/L
  • Second trimester: 0.2-3.0 mIU/L
  • Third trimester: 0.3-3.0 mIU/L


The treatment plan rests with your physician, which takes into account your medical history and current symptoms. For an overactive thyroid, a few treatment options include:

  • Anti-thyroid medication to prevent overproducing hormones
  • Beta-blockers to moderate a rapid heart rate triggered by high thyroid levels
  • Radioactive iodine to slow down your gland
  • A rare approach - surgery to remove the gland

An underactive gland is often treated by taking a synthetic hormone pill every day. The medication will regularise your hormone levels, and you will see the difference when you feel less tired and lose weight. [av_promobox button='yes' label='Book your Health Check now' link='' link_target='' color='blue' custom_bg='#f00' custom_font='#ffffff' size='large' icon_select='no' icon='ue800' font='entypo-fontello'] Keep a tab on diabetes, thyroid, liver, kidneys and more with preventive health checks available only on MediBuddy. [/av_promobox]