Thyroid blood test helps to determine how effectively your thyroid gland is working. The thyroid is responsible for producing thyroid hormones that impact almost every organ of the body. They regulate many of your body's vital processes including metabolism, breathing, digestion, heart rate, and even emotions. Your doctor may advise a Thyroid test if you are experiencing symptoms such as irritability, laziness, fatigue, restlessness, or even weight changes that cannot be explained. The Thyroid blood test includes the thyroid stimulating hormone (TSH), triiodothyronine (T3), and tetraiodothyronine (T4) tests that are done to assess your thyroid hormone levels. The test aids in the diagnosis of thyroid diseases like hyperthyroidism (excess thyroid hormones) and hypothyroidism (low thyroid hormones).

With our complete Thyroid Function test (TFT), you get all three thyroid hormones (TSH, T3, and T4) checked in a single test, so you do not need to book multiple appointments.

The following need to be considered for a TFT blood test.

• Prerequisites : There is no need to fast for our Thyroid test.

• Best Time to Get Tested : A morning sample is preferred for the Thyroid test. Also, you need to schedule this test at the same time of the day each time you take the test.

• Eligibility for Thyroid Test : Thyroid issues can impact anyone, regardless of age. If you experience symptoms suggesting a thyroid problem, are pregnant, have fertility issues, or have a family history of thyroid disease, consider getting a Thyroid test done. Also, if you are already on thyroid hormone regulating medication, the test may be required for dose monitoring.

• • The timing between your last dose of thyroid medication and when your blood is drawn (relevant if your medication contains T3).

  • Stress (including the impact of non-thyroidal illnesses), food, and sleeping habits.

  • Some medications and supplements you are taking.

  • To ensure an accurate diagnosis, discuss these factors with your doctor before getting your Thyroid test done.

• The timing between your last dose of thyroid medication and when your blood is drawn (relevant if your medication contains T3).

• Stress (including the impact of non-thyroidal illnesses), food, and sleeping habits.

• Some medications and supplements you are taking.

• To ensure an accurate diagnosis, discuss these factors with your doctor before getting your Thyroid test done.

• The timing between your last dose of thyroid medication and when your blood is drawn (relevant if your medication contains T3).

• Stress (including the impact of non-thyroidal illnesses), food, and sleeping habits.

• Some medications and supplements you are taking.

• To ensure an accurate diagnosis, discuss these factors with your doctor before getting your Thyroid test done.

The primary role of your thyroid is to regulate your metabolism, which is how your body turns food into energy. Every cell in your body requires energy to operate effectively. When your thyroid is not functioning properly, it can affect your entire body. Having too much or too little of its hormones can make you sick. Symptoms of thyroid disease can vary, and they often resemble those of other medical conditions or natural stages of life. This similarity can make it challenging to determine if your symptoms stem from a thyroid problem or another cause.

Generally, symptoms of thyroid disease fall into two categories: those associated with hyperthyroidism and those linked to having hypothyroidism. These symptoms often contrast because hyperthyroidism accelerates metabolism, while hypothyroidism slows it down.

Now, let us explore the symptoms of hyperthyroidism and hypothyroidism which can guide you in deciding when you might require a TFT test.

Symptoms of hyperthyroidism include:

• Sweating or feeling overly hot

• Losing weight

• Feeling nervous

• Rapid heartbeat

• More frequent bowel movements

Symptoms of hypothyroidism include:

• Feeling extra sensitive to cold

• Gaining weight

• Muscle aches

• Feeling tired

• Feeling weak

• Slow heartbeat

• Constipation

You may also need a thyroid checkup if:

• You are pregnant or planning for pregnancy.

• You are a woman undergoing an investigation for infertility.

• You are on a thyroid hormone replacement regimen.

• You have a family history of thyroid disease.

If you suspect a thyroid issue, getting tested is crucial to confirm the cause and initiate treatment promptly. Additionally, getting tested to monitor treatment for low/high levels of thyroid hormones can help evaluate its effectiveness.

Range for TSH Test Results

Here 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.

Low Levels : A low TSH level typically indicates an overproduction of thyroid hormone, known as hyperthyroidism.

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 recognize that TSH is a labile hormone and is subject to non-thyroidal pituitary influences (glucocorticoids, somatostatin, dopamine, etc.), stress, activity, that can disrupt the TSH/free T4 relationship, 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.

Range for T4 and T3 Test Results

The normal T4 and T3 levels in non-pregnant individuals are given below:

• Total T4: 5.53-11.0 μg/dL

• Free T4: 0.78-2.1 ng/dL

• Total T3: 0.97-1.69 ng/dL

• Free T3: 2.77-5.27 pg/mL

For pregnant individuals, the T4 and T3 range is as follows:

Low Levels : Low levels of T4 and T3 hormones suggest hypothyroidism. This can be caused by Hashimoto's disease, iodine deficiency, inflammation of the thyroid gland, or congenital factors.

High Levels : Elevated levels of T4 and T3 indicate hyperthyroidism. This could be due to factors such as excess iodine in the diet, thyroid gland inflammation, Graves’ disease, or thyroid nodules.

If any of your test parameters show abnormalities, it's recommended to consult with your doctor for better guidance and understanding of your condition.