The TSH with reflex test is carried out to check for any problems in the thyroid gland. The thyroid stimulating hormone (TSH) is produced when the brain releases the hormone thyrotropin-releasing hormone or TRH. This hormone causes the pituitary gland to release TSH. The thyroid stimulating hormone causes the thyroid gland to generate two hormones; triiodothyronine (T3) and thryroxine (T4). These two hormones are responsible for regulating the rate of metabolism in the body. They are also very essential in normal growth rate of the brain within the first 3 years in life. If there are any disorders in TSH production, the child might be mentally retarded.
The test for TSH is carried out to inspect whether or not the thyroid gland is working properly. If the thyroid gland is underactive (hypothyroidism), the patient might experience symptoms such as weight gain, dry skin, constipation, tiredness, feeling too cold or frequent menstrual periods. In contrast, if the gland is overactive (hyperthyroidism), the symptoms will be almost opposite of what is experienced with an underactive thyroid gland. For instance, there will be weight loss, nervousness, diarrhea, feeling hot, irregular menstrual cycles and rapid heart rates.
Rather than determining whether the thyroid gland is hypo or hyper, the test can assist in determining whether the hypothyroidism condition is due to a damaged gland or any other problem. For instance, the hypothalamus or pituitary might have independent problems hence interfering with production of TSH. The test also enable patients and doctors to keep track of the treatment and replacement of medicine to those suffering from hypothyroidism or hyperthyroidism. Treatment of treating overactive thyroid glands may include surgery, radiation therapy or anti-thyroid medicine. To newborn babies, the test is used to double check the diagnosis of congenital hypothyroidism.
Once the test is carried out, the results are interpreted according to the level of TSH present. If the results produce a high TSH result, it may mean that; the patient has an underactive thyroid gland which is not responding to the stimulation of TSH, there might be a problem with the pituitary gland such as a tumor or the patient suffering from hyperthyroidism is receiving excess anti-thyroid medication. Also, a hyperthyroidism patient who is not getting enough thyroid hormone replacement will show high TSH levels after the test. On the other hand, if the TSH levels are low it might be an indication that; the gland is overactive, excess thyroid hormones are being supplemented to hypothyroidism patients, there is damage in the pituitary or a patient suffering from hyperthyroidism is not receiving sufficient treatment.
The TSH with reflex test will only give a glimpse of what is happening to the hormones in the body. The results from the test might vary according to; changes in the proteins which bind T4 and T3, pregnancy, liver disease, systematic illness, estrogen, and resistance to thyroid hormones or use of other drugs. Most of the medications used to treat thyroid problems might interfere with the results hence it is best to discuss with the physician before carrying out the test.