What is tsh in blood test

Your child doesn't have to fast or limit activity before the test. However, some medications may affect test results.

Check with your doctor to see if you should discontinue any medications until after the test. Extreme stress and acute or chronic illness also can affect TSH test results. On the day of the test, it may help to have your child wear a T-shirt or short-sleeved shirt to allow easier access for the technician who will be drawing the blood.

A health professional will usually draw the blood from a vein. For an infant, the blood may be obtained by puncturing the heel with a small needle lancet. If the blood is being drawn from a vein, the skin surface is cleaned with antiseptic and an elastic band tourniquet is placed around the upper arm to apply pressure and cause the veins to swell with blood.

A needle is inserted into a vein usually in the arm inside of the elbow or on the back of the hand and blood is withdrawn and collected in a vial or syringe. After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting the blood for the test will only take a few minutes. Collecting a blood sample is only temporarily uncomfortable and feels like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a day or so.

The blood sample will be processed by a machine. The results are commonly available within a day or two. Whether your child's results are high or low, an abnormal TSH usually indicates an excess or deficiency in the amount of thyroid hormone available to his or her body.

High TSH levels can mean your thyroid is not making enough thyroid hormones, a condition called hypothyroidism. Low TSH levels can mean your thyroid is making too much of the hormones, a condition called hyperthyroidism. If your test results are abnormal, your health care provider will probably order additional tests to determine the cause of your thyroid problem. These tests may include:. Learn more about laboratory tests, reference ranges, and understanding results.

Thyroid changes can happen during pregnancy. These changes are usually not significant, but some women can develop thyroid disease during pregnancy. Hyperthyroidism occurs in about one in every pregnancies, while hypothyroidism occurs in approximately one in every pregnancies.

Hyperthyroidism, and less often, hypothyroidism, may remain after pregnancy. If you develop a thyroid condition during pregnancy, your health care provider will monitor your condition after your baby is born. If you have a history of thyroid disease, be sure to talk with your health care provider if you are pregnant or are thinking of becoming pregnant.

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. TSH Thyroid-stimulating hormone Test.

What is a TSH test? Other names: thyrotropin test. What is it used for? Also, don't skip doses or stop taking the drug because you're feeling better. If you do, the symptoms of hypothyroidism will gradually return. Certain medications, supplements and even some foods may affect your ability to absorb levothyroxine.

Talk to your doctor if you eat large amounts of soy products or a high-fiber diet or you take other medications, such as:. Levothyroxine is best taken on an empty stomach at the same time every day. Ideally, you'll take the hormone in the morning and wait an hour before eating or taking other medications.

If you take it at bedtime, wait four hours after your last meal or snack. If you have subclinical hypothyroidism, discuss treatment with your doctor. For a relatively mild increase in TSH, you probably won't benefit from thyroid hormone therapy, and treatment could even be harmful. On the other hand, for a higher TSH level, thyroid hormones may improve your cholesterol level, the pumping ability of your heart and your energy level.

Although most doctors recommend synthetic thyroxine, natural extracts containing thyroid hormone derived from the thyroid glands of pigs are available. These products contain both thyroxine and triiodothyronine. Synthetic thyroid medications contain thyroxine only, and the triiodothyronine your body needs is derived from the thyroxine. Extracts are available by prescription only and shouldn't be confused with the glandular concentrates sold in natural foods stores. These products aren't regulated by the Food and Drug Administration, and their potency and purity isn't guaranteed.

You'll likely start by seeing your family doctor or a general practitioner. In some cases, you may be referred to a doctor who specializes in the body's hormone-secreting glands endocrinologist. Infants with hypothyroidism need immediate referral to a pediatrics endocrinologist for treatment.

Children or teens need to see a pediatric endocrinologist if there is any uncertainly about starting levothyroxine or proper dosing of the hormone. Here's some information to help you get ready for your appointment and know what to expect from your doctor.

Preparing a list of questions will help you make the most of your time with your doctor. For hypothyroidism, some basic questions to ask include:. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version. Diagnosis In general, your doctor may test for an underactive thyroid if you are feeling increasingly tired, have dry skin, constipation and weight gain, or have had previous thyroid problems or a goiter.