Controlled by the hypothalamus and pituitary glands, the thyroid is an endocrine gland located in the neck of the human body. This gland produces thyroid hormones triiodothyronine (T3) and thyroxine (T4). T3 and T4 regulate metabolism and other systems in the body. Thyroid tests are done to assist in the diagnosis of disease. Thyroid medication prescribed by a physician duplicates the normal human thyroid exactly.
Things You'll Need
- Test results from your physician
Test Results for Thyroxine (T4) Levels
Go to the clinic and have your blood drawn for the T4 level tests. One particular test is called radioimmunoassay (RIA). It measures thyroid function and how much T4 is in the blood. A thyroid-stimulating hormone (TSH) blood test is used to check for potential thyroid problems. The Free T4 test is one that measures the T4 not bound with proteins and can be very useful in managing hypothyroidism.
Study the results you receive from your doctor. If your T4 level is between 4.5 and 12.5, it is considered in the normal range. A low T4 level may mean a diseased thyroid gland or a non-functioning pituitary gland which is not stimulating the thyroid to produce T4. If the T4 level is low and TSH is not higher, the pituitary gland may be the cause of the hypothyroidism. If the T4 is low and the TSH is high, it may confirm that the thyroid gland, not the pituitary gland, is responsible for the hypothyroidism.
If test results indicate high or low T4, or T3 which can't be explained, it may be due to an increase or decrease of protein globulin (TBG). This situation causes no problems except falsely elevating or lowering the T4 level. This causes a frequent misdiagnosis of hyperthyroidism or hypothyroidism, where there is no thyroid disorder and medication is not required. Most thyroid hormones in the blood are connected to TBG. If there is an excess or deficiency of TBG, it changes the T4 or T3 measurement.
Inspect your test results for abnormal readings. If abnormal results are found, this could indicate an overactive thyroid or an underactive thyroid.
An overactive thyroid creates the condition of hyperthyroidism. Symptoms include rapid heart rate, weight loss, nervousness, a feeling of being too hot, diarrhea or irregular menstrual periods in women.
An underactive thyroid is called hypothyroidism. Symptoms include constipation, weight gain, fatigue, dry skin, a feeling of being too cold or frequent menstrual periods in women.
Tips & Warnings
- If you are advised by your physician that your tests are normal but you have symptoms or risk factors for thyroid disease see an alternate physician.
- If you are prescribed thyroid medicine, it's important to follow the instructions exactly.
- Advise your physician if you have had tests in which radioactive materials were used, or had X-rays that used iodine dye within the last six weeks. Either of these would affect the outcome of the test results.
- Photo Credit senior doctor 12 image by Paul Moore from Fotolia.com
What Is a Low Thyroid Number?
A low thyroid number is when blood test results indicate your thyroid is not functioning properly. Low levels of the thyroid hormone...
How to Read Thyroid Blood Test Results
The thyroid is a very complicated gland. It is responsible for producing hormones that direct our metabolism. As a result, symptoms of...
What Is a Normal T4 Thyroid Level?
Using the Free T4 test, if your result is less than .8, then you may have an underactive thyroid. Remedies. If you...
What Are Normal T3 & T4 Blood Test Readings?
T3 and T4 are thyroid hormones that regulate metabolism and other body functions. Laboratory tests determine the level of these hormones in...
Is 1.0 Low for Thyroid Function?
The first test a doctor will give you is the T4 test, ... There are two versions of T4--serum thyroxine and free...
What Problems Occur From Low Levels of T3 & T4 Hormones?
When levels of T3 and T4 are low, ... What Are Normal T3 & T4 Blood Test Readings? What Is a Normal...
How to Fill Out a T4 Slip
Canada employers fill out T4 slips for tax reporting whenever the employer has paid remuneration such as salary, gratuities, ... Read Article....
How to Understand Hyperthyroid & Hypothyroid Numbers
How to Understand Hyperthyroid & Hypothyroid Numbers. ... T3 and T4 -- present in the blood, and also the level of TSH,...
Normal TSH & T4 Levels
Other People Are Reading. How to Read T4 Thyroid Test Numbers; ... A TSH (Thyroid Stimulating Hormone) test is performed to check...