Health Test

Is Fasting required for Thyroid test and Other Questions Answered

The thyroid is a small, butterfly-shaped gland. It is located near your throat and makes hormones that play an important role in regulating your weight, body temperature, and even your mood. Primarily, thyroid hormones regulate the way your body uses energy.

Having a healthy level of thyroid hormones helps your body perform metabolic functions optimally. Book a thyroid panel and know about your thyroid gland health. 

Got questions about thyroid tests? Here we are providing answers to some of the most frequently asked questions about thyroid tests: 

What are the different types of thyroid blood tests?

Thyroid function tests are a set of blood tests used to measure how well your thyroid gland is working. They help detect an overactive or underactive thyroid gland and also give hints about other related conditions. There are three main types of thyroid blood tests:

  • TSH test: A thyroid stimulating hormone (TSH) is not released by the thyroid gland. It is made in the pituitary gland in the brain. When thyroid levels in your body get low, the pituitary gland makes more TSH which serves as a signal for the thyroid gland to compensate and release more thyroid hormones. When thyroid levels are high, the pituitary gland makes less TSH. Hence, the TSH levels that are too high or too low can tell if your thyroid is working well.
  • T4 test: Measures the blood level of the hormone T4 (thyroxine).
  • T3 test: Measures the other major thyroid hormone T3 (triiodothyronine) in the blood.

When do I need a thyroid test?

One may need a thyroid test if you think you have symptoms of underactive or overactive thyroid gland. Having excessive thyroid hormones in your blood is called hyperthyroidism and insufficient thyroid hormones is known as hypothyroidism.

Symptoms of hypothyroidism include following:

  • Weight gain
  • Tiredness
  • Low tolerance for cold temperatures
  • Irregular menstruation
  • Constipation
  • Hair loss

Symptoms of hyperthyroidism include following:

  • Weight loss
  • Tremors in the hands
  • Increased heart rate
  • Puffiness
  • Bulging of the eyes
  • Anxiety
  • Diarrhea

Do I need to fast for my thyroid test?

Usually,no special precautions including fasting need to be followed before taking a thyroid test. However, your pathologist can guide you better. For example, if you have to undergo some other health tests along with thyroid hormone levels, you may be asked to fast for 8-10 hours. Drinking water doesn’t come under violation of fasting. 

Should I take thyroid tablets before thyroid blood test?

If you are taking medicines for thyroid conditions (thyroxine) to treat your thyroid disease, it is recommended that your blood sample be taken before you take your dose for that day. Have your medicine post the test. Always consult your doctor for such suggestions as they know your health condition best and might advise otherwise too.

Is there any common medicine that interferes with thyroid function tests?

Biotin (Vitamin B7) is a commonly taken over-the-counter supplement that can lead to some aberrancy in your thyroid function tests even when the values are actually normal. Avoid taking biotin 2 days before a thyroid function testing.

What is the normal reference range for thyroid function tests?

Reference ranges for each value under thyroid hormone is not consistent for everyone. It differs based on certain parameters such as age, health condition, and the laboratory that performs the testing.
Common reference ranges for the thyroid panel are enlisted here:

  • TSH: 0.4 to 4.5 mIU/L (may be as high as 7.5 mU/L in 70 year olds)
  • Free T4: Often falls between 0.8 and 1.5 ng/dL in adults.
  • Total T3: 75 to 195 ng/dL (1.1 to 3 nmol/L)

Check your test report or ask your doctor for the normal/reference range. Most laboratory reports mention the reference ranges applied to your thyroid test, however, consult an expert to interpret the results. Also, since it is a panel test, values are generally interpreted together and not seen as individual numbers.

What should I take care of after getting tested for thyroid hormones?

Once the blood sample for thyroid test is drawn, you can return to normal activities, including driving. A simple thing that you can follow is to avoid strenuous activity with the arm from where the sample was taken for a few hours after the test. If you experience any pain or bleeding, apply (and do not rub) ice packs

Can I take thyroid tests during pregnancy?

Yes, you can if need be.In fact,it is not uncommon to have thyroid changes during pregnancy. While overactive thyroid affects about one in every 500 pregnancies, underactive thyroid happens in around one in every 250 pregnancies. If you have a pre-existing thyroid condition or develop a thyroid condition during pregnancy, your doctor will monitor your condition and ask for blood tests too. Most likely, your thyroid hormone levels will be checked every 4 to 6 weeks during the first half of your conception, and at least once after 30 weeks.


A thyroid panel test can help identify various conditions including hypothyroidism, hyperthyroidism, Graves’ disease, and thyroid cancer. For all your lab test related needs, visit Metropolis.

Like
Like Love Haha Wow Sad Angry

Leave a Reply

Your email address will not be published. Required fields are marked *