The thyroid is a gland that is responsible for controlling the metabolism of the body. The metabolism of the body decides the rate of the chemical reactions taking place in the body. The amount of thyroxine secreted by the thyroid is controlled by the thyroid stimulating hormone (or the TSH). The TSH test is used to measure this hormone. The thyroid is located near the throat and is a small gland shaped like the butterfly. The hormone produced by the thyroid gland called thyroxine would regulate how the body uses energy. It would play a huge role in regulating body temperature, the weight, muscular strength and even the mood.
The TSH is produced by a gland called the pituitary. It is the master gland. When the thyroxine levels in the blood are low, the pituitary gland would produce more TSH asking the thyroid to produce more hormones. If the thyroxines levels are high, on the other hand, the pituitary gland would produce less TSH. Too high or low TSH levels generally indicate that the thyroid is not performing correctly. The SGPT test is quite similar, which is used to measure the proper functioning of the liver.
Why does the TSH test become necessary?
The TSH test might be needed if symptoms of too much thyroxine can be seen in the blood (hyperthyroidism) or too little of it (hypothyroidism). Hyperthyroidism, or an overactive thyroid, would have the following symptoms:
- bulging of the eyes
- loss of weight
- increased heart rate
- tremors in the hand
- difficulty in sleeping
Hypothyroidism, or an underactive thyroid, would have symptoms like
- loss of hair
- gain of weight
- low tolerance towards cold temperatures
- menstrual periods becoming irregular
What is the procedure of the TSH test?
The TSH test would be quite similar to a normal blood test. The technician would collect a sample of blood from a vein in the arm with the help of a small needle. A small amount of blood would be collected into the vial or test tube after the needle has been inserted. The test would not even take 5 minutes. It is quite similar to the ESR blood test, which also needs the collection of a blood sample to determine if there is any inflammation in the blood.
How would someone prepare for the test?
There is no special preparation required for a TSH blood test. If the doctor has ordered for some other blood tests, there might be a requirement for fasting. This would mean that you would need to plan properly as you cannot eat for several hours before the test. The doctor would also tell you if there are any other special instructions that you would need to follow. The risk factor in any blood test is quite low. A slight pain or bruising might be felt at the spot but the symptoms would go away soon enough.
What is indicated by the results of the tests?
If the levels of TSH is high, it would mean that the thyroid is not producing enough hormone. This condition would be called hypothyroidism. If the levels of TSH is low, on the other hand, it would mean that the thyroid is producing too much of thyroxine, resulting in hyperthyroidism. However, the test would not explain why the case is so. There might be the need to go through some additional tests if the test results are abnormal. These tests might include:
- T3 thyroid hormone tests
- T4 thyroid hormone tests
- Tests diagnosing Graves’ disease, which is an autoimmune disease causing hyperthyroidism
- Tests diagnosing Hashimoto’s disease, which is an autoimmune disease causing hypothyroidism
The TSH test can thus be a good indicator of the status of the thyroid gland.