What is a Thyroid Test?
The thyroid function test measures the levels of thyroid-stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) in the blood. The thyroid is a small gland in the neck at its lower-front part that produces thyroid hormones. The thyroid gland makes two thyroid hormones: thyroxine (T4) and triiodothyronine (T3).
Types of Thyroid Diseases Diagnosed by Thyroid Test:
Thyroid hormones regulate metabolic activities in the body, so the alteration in the production of these hormones causes hyperthyroidism and hypothyroidism.
Hyperthyroidism– It is an over-functioning thyroid condition, where the thyroid gland produces an excess of thyroid hormone. This leads to increased metabolic functions, accelerated heartbeat, unintentional weight loss, enhanced sweating and irritability.
Hypothyroidism– It is a poor functioning thyroid condition, where the thyroid gland produces low thyroid hormones. Hormone deficiency causes low metabolic activity in the patient’s body. It results in fatigue, constipation, weight gain, cold sensitivity, dry skin, altered heart rate and change in body temperature.
The other conditions that affect the thyroid gland which in turn leads to hyper or hypothyroidism include:
- Thyroiditis
- Grave’s disease
- Hashimoto’s disease
- Goiter
- Thyroid nodule
- Thyroid cancer
How are the Samples Collected?
The thyroid function test needs a blood sample collection. The blood sample is taken through venipuncture.
- The skin area of the patient is disinfected using a suitable disinfectant.
- Using a sterilized needle, blood is drawn from the vein.
- Drawn blood is collected in the sterilized vial or test tube. Vials are preferred for blood sample collection.
The blood sample is further submitted to the pathology labs for thyroid test. The name, age of the patient, and the test name are recorded along with. The thyroid test at home is a convenient choice for patients, as it doesn’t require any specific criteria. Most of the pathology labs in India offer the thyroid function test. Patients can also request for the home sample collection.
Understanding the Thyroid Test results
Thyroid test results determine the TSH, T3 and T4 levels in the blood. High TSH level indicates that the thyroid is not producing enough thyroid hormones and suggests hypothyroidism. If the TSH level is low, then excess thyroid hormone has been produced by the thyroid gland, causing hyperthyroidism. The thyroid function test, however, does not specify why the TSH is low or high. More tests are performed to understand the situation better. Agilus Diagnostics offers test report time within 24 hours.
TSH results
TSH blood test helps understand the functioning of the thyroid gland.
Normal TSH Level
The normal range of TSH for an average adult is 0.4 to 4.0 mIU/L (milli-international units per liter). A value above this range indicates hypothyroidism, while a value below the normal range indicates hyperthyroidism.
High TSH Level
If in the blood, a high TSH level has been reported, then there is an underactive thyroid and the body does not produce enough hormones, which leads to a hypothyroidism condition. So, the pituitary gland in response continues releasing TSH in the blood.
Also Read – What Is Hyperparathyroidism and How Does It Occur
Low TSH Level
If in the blood, the low TSH level has been reported, then the patient has an overactive thyroid. If the gland produces an excess hormone, it causes hyperthyroidism. This results in less or no production of TSH by the pituitary gland.
T4 results
T4 test, also known as the thyroxine test is one of the common thyroid function tests that measure the bound and free hormone in the bloodstream of the patient.
Normal T4 Level
The normal t4 level range in adults is 0.8 to 2.8 nanograms per deciliter (ng/dL). The value lying outside this range leads to thyroid problems.
High T4 Level
When a high blood level of T4 has been reported, then there is an overactive thyroid gland in the patient leading to hyperthyroidism.
Low T4 Level
On the other hand, if there is a low level of T4 in blood, then it signals hypothyroidism in the patient. It means the patient has an under-active thyroid gland.
T3 results
T3 Test helps measure the levels of the hormone triiodothyronine. However, based on the T3 test only, the conclusion cannot be drawn of whether it is the signs of an overactive thyroid gland or an under-active function of the same. Results of TSH and T4 are also taken into account for proper clinical analysis.
Normal, High & Low T3 Level
The normal range for the T3 is 100 to 200 nanograms per deciliter (ng/dL). A high level of T3 is also seen in an autoimmune disorder called Grave’s disease. A low level of T3 causes hypothyroidism.
Agilus Diagnostics, a subsidiary of Fortis Healthcare Limited
