Thyroid Function Test (TFT): Causes, Symptoms, and Report Analysis

The thyroid controls body temperature, metabolism, and other metabolic activities, such as heart rate and energy expenditure. Thyroid hormone levels can either be over- or underproduced and can affect overall health. The Thyroid Function Test (TFT) is a set of blood tests that determines the levels of thyroid-related hormones and therefore the thyroid gland's function. Molecular Diagnostics and Therapy is a diagnostic centre that provides services of molecular laboratory testing for the evaluation of different health conditions.

A TFT test is typically performed in individuals with an unexplained loss or gain of weight, fatigue, hair loss, or difficulty with mood, as well as those with an irregular heartbeat (pulse). Knowing what the thyroid test levels of TSH, T3, and T4 are normally is very beneficial to patients in the interpretation of their thyroid test results and when discussing results with their doctor. 

Why Is a TFT Test Recommended?

A TFT test may be ordered if a person has symptoms that might be a sign of an underactive or overactive thyroid gland. A TFT may also be recommended during pregnancy when clinically indicated, as part of selected health assessments, or to monitor an existing thyroid condition. A test can assist with the investigation of unexplained weight change (loss or gain), loss of energy, irregular periods, increasing or decreasing heart rate, hair thinning, and more. It is also important for monitoring responses to thyroid medications and deciding if necessary adjustments of treatment are needed.

Causes of Thyroid Hormone Imbalance

Medical disorders can cause levels of thyroid hormone to become abnormal. When the thyroid gland does not make sufficient amounts of hormone, it is called hypothyroidism. Common causes are Hashimoto's thyroiditis, an autoimmune disorder of the thyroid, iodine deficiency in some instances, thyroid surgery, and some medications. Hyperthyroidism occurs when the thyroid produces more hormones than are needed. Hyperthyroidism can be caused by Graves' disease, overactive thyroid nodules, or certain forms of thyroid inflammation. Even taking more thyroid hormone medicine than directed will also alter hormone levels. In a few cases, pregnancy, some medications, and problems with the pituitary can affect thyroid blood measurements. Doctors consider a patient's medical history, symptoms, physical examination, and thyroid test results together to identify the possible cause of a hormone imbalance.

Common Symptoms of Thyroid Problems

Symptoms are affected by whether the thyroid is underactive or overactive. Individuals with hypothyroidism may feel tired, gain weight, have dry skin, constipation, hair loss, feel cold more of the time, and struggle to concentrate. There may also be other changes to the menstrual period in some people. Symptoms of hyperthyroidism include weight loss, sweating, anxiety, shaking hands, frequent stools, insomnia, and/or a more rapid pulse. Some people with hyperthyroidism may experience increased appetite and heat intolerance rather than feeling cold more easily. There are also other medical conditions that can have these symptoms. The thyroid function test is used to give the doctor a reason to suspect that thyroid hormone imbalance is contributing to their symptoms.

How to Read a Thyroid Test Report?

Thyroid test results should be interpreted together, particularly TSH and free T4, while T3 measurements may provide additional information when clinically indicated. When TSH is elevated and T4 is low, it is often a sign of primary hypothyroidism, or an underactive thyroid gland. A low level of TSH coupled with an elevated level of T3 or T4 can be an indication of hyperthyroidism. In subclinical hyperthyroidism, however, low TSH levels with normal T3/T4 occur. Again, if the TSH is elevated and T4 is normal, subclinical hypothyroidism is suspected. Not all abnormal findings are life-threatening. However, repeated testing along with thyroid antibody testing and other tests may be suggested based on results and symptoms.

Preparation for a TFT Test

Generally, a thyroid screening test does not need to be done while fasting. Instructions on how to prepare may, however, change, depending on the tests to be performed. Thyroid medication, supplements, and other medications may affect the results of these tests and should be mentioned to a doctor. Do not discontinue medication without a healthcare provider's instruction.

Conclusion

Thyroid function tests (TFTs) help doctors assess thyroid hormone levels in the blood and investigate symptoms that may be related to thyroid disorders. For an individual to be an active participant in their own healthcare, it is beneficial to understand the normal ranges of measurement for their thyroid tests: TSH, T3, and T4. Molecular Diagnostics and Therapy provides diagnostic testing services that support the investigation and monitoring of thyroid-related health conditions. Follow-up thyroid tests may be indicated by a doctor if any thyroid hormone levels need to be monitored, the treatment result is being assessed, or there may be a need for additional treatment.