Thyroid Profile

What is the thyroid profile test?

A thyroid profile test is a panel or series of blood tests done in order to understand whether or not your thyroid gland is functioning properly or not. The thyroid gland is probably the most critical endocrine gland in the human body that controls growth and metabolism.

Both high and low thyroid hormone levels could affect several organ systems of the body and have chronic side-effects starting from weight disturbances to sleep disorders. A thyroid profile test checks the following thyroid hormones:

– TSH or thyroid secreting hormone
– T4
– T3
– Thyroglobulin Antibody
– Anti-thyroid antibody

Why has the doctor asked me to under a thyroid profile test?

Individuals with abnormal thyroid levels tend to show these symptoms

– Unexplained weight changes either weight gain or weight loss
– Appetite changes
– Changes in levels of energy
– Anxiety and fast heartbeat
– Sluggishness and fatigue
– Depressive tendencies
– Cold sensitivity
– Hair loss
– Puffy face
– Sleep problems such as insomnia

In addition to these, there are certain cases where thyroid hormone imbalance is seen as a result of autoimmune conditions such as Hashimoto’s disease. Here, the body’s immune system starts destroying healthy thyroid gland cells resulting in abnormal thyroid levels. If your doctor suspects any of these conditions as seen through the symptoms, he/she will ask you to undergo a thyroid profile test.

What are the symptoms of abnormal thyroid levels?

The most common symptoms of hypothyroidism (inactive thyroid gland) are:

– Weight gain
– Cold sensitivity
– Hoarse voice
– Hair loss
– Swelling of face and limbs
– Lethargy
– Irritability
– Depression
– Constipation

The following are symptoms of hyperthyroidism ( overactive thyroid gland):

– Unexplained weight loss
– Appetite changes
– Tremors
– Anxiety and panic attacks
– Palpitations
– Shortness of breath
– Dry and scaly skin
– Anemia
– Joint pains
– Muscle cramps
 

What are the main functions of the thyroid hormones?

The main functions of the thyroid hormones are:

– Regulation of healthy metabolism and maintain basal metabolic rate
– Work with growth hormones to ensure healthy skeletal system
– Protein synthesis
– Neural development
– Stimulation of vitamin metabolism
– Maintenance of body temperature

How do I prepare for the thyroid profile test?

– Inform your doctor about all the medications including supplements and herbal products you are on. You might need to stop consuming some of these in case they impact thyroid hormones.

– Tell your doctor if you are pregnant. Pregnancy affects thyroid levels.

– Medications such as aspirin, corticosteroids, lithium, potassium, etc
tend to interfere with thyroid levels so your doctor will advise that you refrain from taking these before the sample collection.

– TSH and T4 tests individually do not require fasting but the total thyroid profile test might require overnight fasting, though in most cases it is done without fasting. You can only drink water before the test, in case fasting has been advised.

– Studies suggest that TSH levels reach the peak value from 2 am to 4 am and take a dip between 4 pm and 8 pm. Thus, the morning is the best for going for this test.

What is the price of the thyroid profile test in India?

The price of thyroid profile test in India starts from Rs 900 and can go as high as Rs 1800 depending on the city and the type of diagnostic centers.

How is the thyroid profile test performed?

The thyroid profile test is performed by a simple venipuncture procedure. Here, a blood sample is collected from the arm. A tourniquet or elastic band is tied across the upper arm tightly as this increases the pressure of the blood in the veins. This makes it easy to locate veins. Once the vein has been located, a syringe is slowly injected and blood is drawn from this vein. The blood gets collected in a vial. Once the blood has been drawn, the syringe is slowly withdrawn and a sterile gauze is used to cover the puncture site to prevent bleeding and infection. The sample is sent to the lab for testing.

When will I get my thyroid profile report?

It usually takes a period of 2-3 days for the complete thyroid profile report to be available.

What is the significance of TSH reading?

TSH provides the best and most accurate picture of your thyroid gland’s functioning.  The level of TSH is usually treated as an early warning system for thyroid disorders. High TSH indicates that the thyroid gland is not creating enough thyroid hormones and is indicative of an underactive thyroid or hypothyroidism. Conversely, a low TSH means too much thyroid hormone secretion or hyperthyroidism. Occasionally, a low TSH may result from an abnormality in the pituitary gland, which prevents it from making enough TSH to stimulate the thyroid (secondary hypothyroidism). In most healthy individuals, a normal TSH value means that the thyroid is functioning properly.

What is the T4 hormone?

The T4 test and the TSH test are the two most common thyroid function tests. They’re usually ordered together. The T4 test is known as the thyroxine test. A high level of T4 indicates an overactive thyroid (hyperthyroidism). Symptoms include anxiety & panic attacks, sudden weight loss, tremors, and diarrhea. Most of the T4 in your body is bound to protein. A small portion of T4 is not and this is called free T4. Free T4 is the form that is readily available for your body to use. Sometimes a free T4 level is also checked along with the T4 test.

What is the T3 hormone and what is its function?

Triiodothyronine or T3 is a hormone secreted by the thyroid glands and is important for the metabolism of your body, including the heart rate and temperature. About one-fifth of T3 is secreted by the thyroid glands; the rest 80% is formed by another thyroid hormone T4 (thyroxine). Most of T3 circulates in the body in the bound form-TBG (thyroid-binding globulin) being the major binding protein. T3 tests are often useful to diagnosis hyperthyroidism or to determine the severity of hyperthyroidism. Patients who are hyperthyroid will have an elevated T3 level. In some individuals with a low TSH, only the T3 is elevated and the FT4 or FTI is normal.

What is the difference between T4 and FT4?

T4 is the measure of thyroxine hormone circulating in the bloodstream. It is the sum total of both bound and free T4 hormones. FT4 is a measure of free T4 hormones that remain in the unbound state and can thus enter the body cells and affect the body tissues. The T4 reading along with TSH provides the most accurate picture of your thyroid gland.

What does the thyroglobulin antibody mean?

Thyroglobulin is a specific type of protein that is produced by the thyroid gland and is involved in the production of thyroxine. This serves an important role in maintaining healthy reserves of iodine and thyroid hormones in the body. In healthy individuals, the level of thyroglobulin is quite low and only in cases of malignancy does the level surge.

What is reverse T3?

Reverse T3 is the inactive form of the actual T3 hormone. It has the same structure as that of T3 and the only difference is the position of the iodine atom in the molecular structure. This factor makes it biologically inactive. Measurement of this thyroid hormone is not considered clinically useful.

What is meant by the antithyroid antibody?

Antithyroid antibodies are specific antibodies created by the body’s own immune system that attack and destroy healthy thyroid cells. This is treated as the body’s autoimmune response to healthy body cells. This factor is considered responsible for Hashimoto’s disease and Grave’s disease. These antibodies target critical points of the thyroid gland and impact the levels of thyroid peroxidase, thyroglobulin, and TSh receptors. The additive effect is abnormal thyroid hormone secretion which can lead to an overactive thyroid or an underactive thyroid.

What medications can affect thyroid levels?

The following medications can affect thyroid levels and you should inform your doctor if you are on these, prior to the test:

– Estrogen tablets or birth-control pills (OCPs)
– Biotin supplements
– SSRIs (anti-depression pills)
– Anti-seizure medications
– Testosterone supplements
– Cancer drugs

What is the normal reference range for the thyroid profile test?

Can pregnant women undergo this test?

Yes, since pregnancy does affect the thyroid levels and also since pregnancy can lead to post-natal hypothyroidism it is important for pregnant women to undergo this test.

Is this test recommended for children?

Yes, if the child is showing symptoms of abnormal thyroid functioning, the doctor may prescribe a thyroid profile test.