Total Thyroxine (T4) Test: Uses, Side Effects, Results


The total thyroxine test is used to diagnose thyroid disorders . Thyroxine (T4) is a thyroid hormone, and test measures, as in your blood.Some thyroid diseases are tied too small T4, while others are too connected.

Other names for this test is a common T4 test, the total concentration of T4 and the thyroxine screen.

Try Purpose

The thyroid gland is iron in front of its throat, which makes hormones and regulates several important functions, including energy, weight, body temperature and mood.

t4 works on your body in a couple of shapes. A form of protein links to perform certain tasks, and the other way does not allow different tasks.The T4 Total test verifies the general level T4, which includes both forms and T4 free, which is a form that is not associated with the protein.

The level of all T4 depends significantly on the amount of binder protein in the blood, and the amount of protein affects many conditions without shapes .Therefore, the total T4 measurement can not accurately reflect the status of the thyroid gland.For this reason, the free T4 test, which measures only the active and unrelated T4 part in the blood, is considered an excellent test, and has largely supplanted the total T4 test in clinical medicine.

The health care provider can enjoy the total T4 test if you have symptoms that could indicate hypothyroidism (Thyroid iDeractive) or hypertotysic intertaites (especially if you have other factors of Risks women and more60, or has members of the family with thyroid disorders .

It is likely that your medical care provider will meet other thyroid dimensions at the same time as the T4 test.

They generally include hormone tests, stimulating the thyroid gland (TSH) and trioodironin (T3).Tests to observe antibodies that can indicate autoimmune diseases can also be performed simultaneously or can be done as a posterior access to with abnormal testing of thyroid function .

Low levels T4 can lead to an increase in tests to determine if you have a autoimmune thyroid disease, called Hashimoto Thyaredite. High levels can lead to tests for the tombs of the disease , thyroiditis or sin.

T4 and other thyroid tests are performed on blood samples. Take samples of blood quite fast, simple and low risk.



The most common risks faced by people from the blood test.A small pain or mild brunette, which should go quickly.

Some people, especially those who are afraid of needles, can experience dizziness, nausea or calls in the ears during or immediately after the blood draw.If this happens, allow someone at the medical center to know. The objects are well equipped to deal with this reaction, which generally includes lying for some time and drinks a little water.

If you have a history of negative reactions, you can organize it to organize it inside and from the test object.

Let the nurse or phlebotomist, who draws his blood, know before the test, if he had bad blood reactions, drawing in the past, you have bleeding or taking bleeding preparations, or if His leather tears or bruises are easy.They must be able to soften any risk, these elements can create.

Before the test

Blood for T4 and other thyroid tests, as a rule, can be drawn at any time of the day.It does not require publication (avoiding food) in advance.

Make sure your insurance card and any written orders that your medical provider has given you.

Talk to your health care provider about any medication that you accept and can change the results of your tests.

You may need to take a break from certain medications, including:

  • Drugs containing hormones (ie ,, Fertility control tablets, estrogen,androgen)
  • steroids
  • Some cancer drugs
  • medical preparations (if it is not marked by what so effective is it The medication)

Other medications can affect the results,And you can also complement it, so make sure your health care provider knows that everything you take. Biotin, in particular, avoids thyroid analyzes. Patients should stop biotin three days before the thyroid gland test.

Time and location

The same to extract blood It only takes a few minutes. If you receive some tests, it may take a little more.If the blood is directed to the office of your health during destination, you must add very little time for the length of the destination.

Go to the Mass Laboratory, you may need a more time commitment.If you have a planned time for your test, it is necessary to arrive quite early to register and pay any patch that may be associated during. If you are worried about the mass, you can also get a few minutes to sit and relax.

Laboratories are often busy, so if you throw it, you can call in advance or strive for daylight (for example, early in the morning), when they tend to be less crowded,

What to use

You must be able to stay on your own clothing for blood drawing. It must display your hand, so that the sleeves that are short or can be easily removed.

In the case of a domestic spell, you may want to wear flat shoes and clothing that is not limited and narrow. .

Food and Beverages

At any time you have blood, you must be sure that it is well moistened.That helps his veins to maintain their shape, which means that they are easier to find and insert a needle successfully.

Since you do not need to try before the T4 test, this is a good idea to have something in the stomach, which can help avoid any nausea.

If your medical provider orders other tests at the same time, some may require publication. Be sure to follow all instructions that specify the professional and / or laboratory that performs the test.

( Cost and medical insurance

, as a general rule, the tests of the Function of the thyroid gland is covered by insurance when considered necessary from a medical point of view.If you have any questions, be sure to call your insurance company in advance to see what happens if it is available, outside the pocket expenses you can find.

Laboratory costs for shared T4 may vary from 45 to approximately $ 130. If it is not insured, you can find additional charges, especially if your health care provider requests more than one test.A complete set of thyroid tests can cost more than $ 500.

The office of your health care provider, the insurance company and the laboratory should help you determine the cost before obtaining tests.

During the test

Before drawing the blood nurse or phlebotomist, you can ask you to confirm some information, such as your name, date of birth, health care provider, ordering a test,And what test he sent. This should help prevent mistakes.

Previous test

You will be asked to expose your hand and the insertion area will be cleaned with alcohol.A person who makes a drawing joins a strip around the top of the arm to catch the blood in his veins, which makes it easy for the search for a good vein and insert a needle. If your veins are well outstanding, you can ask for a fist.

Throughout the test

After identifying a good vein, the needle will be inserted. The group will be released to push the blood again, and the bottle attached to the needle will be filled.Depending on how many tests are requested, the nurse / phlebotomist may need to change the bottle once or several times.

After drawn by the needed blood, the insertion site will be bound.

After trying

Most of the time you can leave immediately after the blood drawing. If you have any negative reaction, allow someone to know about the object so you can get adequate care.Usually, even with a bad reaction, people are in order after a few minutes.

After test

may have small pain and bruising around the site, where the needle was inserted, which is usually going in a short time.If you have a problem or ask, be sure to contact your health care provider.

Control side effects

If the site hurts, you may want ice or have extreme pain.You should not have other prolonged effects of the simple blood drawing.

Interpretation results

In adults, a typical range of T4 free is 0.9 to 2.4 nanograms for decilters.Total T4 has a tendency to vary more depending on age.

High level of high level T4 may indicate hyperthyroidism, thyroiditis or zeomet. This can lead to additional tests for serious illness.

The non-uniform level T4 can be a sign of hypothyroidism, problems with their pituitary glands, malnutrition or iodine deficiency or other disease. This can lead to additional tests for Hashimoto thyroiditis.

However, the abnormal T4 level usually does not usually lead to a diagnosis. Your health care provider probably analyzes it together with T3 and TSH levels.


As soon as you have Results, your health care provider may want you to return to analyze additional testing or treatment options, depending on the diagnosis.If you do not understand about your results in a timely manner or if you do not understand what they mean, see the office of your health care provider.If you are diagnosed with a thyroid gland, then it is time to observe the treatment options, since early treatment is the key.

The word of the information obtained from table

Thyroid disorders are common (especially in women) and The high cell.Many thyroid diseases are administered by making medications and, possibly, making some changes in the diet.How to diagnose thyroid disorder, can be scared, even value is what it means that you can begin to treat and manage the condition that feelings should mean and function better.

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