Monday, June 27, 2022
HomeEditor PicksWhat Blood Test Is Used To Check Thyroid

What Blood Test Is Used To Check Thyroid

What Happens After A Fine Needle Aspiration Biopsy

Blood Tests for Thyroid Cancer Diagnosis ?

Most people will be able to resume their normal activities right away. You can remove your bandage within a few hours.

The site of the biopsy might be sore for a day or two after the procedure. You can take over-the-counter pain medicines if you need to. Follow any other specific instructions that your healthcare provider gives you.

It may take several days to get your test results from the pathology lab. Ask your healthcare provider when you can expect to get your results back.

If your thyroid nodule is not cancer, you might not need any further treatment. Your provider may want to monitor your nodule, though, and you might need another biopsy in the future. In some cases, your healthcare provider may offer thyroid hormone pills. These can sometimes decrease the likelihood of nodules growing back.

You will probably need surgical treatment if your nodule appears cancerous. Luckily, most thyroid cancers are curable.

Sometimes, the pathologist cannot determine for sure whether your nodule is cancer. In this case, your healthcare provider might recommend a repeat biopsy or surgery. Whatever your test results, you can work with your healthcare provider to develop the best possible treatment plan for you.

What Blood Tests Are Done To Test The Thyroid

Thyroid blood tests include:

These tests alone arent meant to diagnose any illness but may prompt your healthcare provider to do additional testing to evaluate for a possible thyroid disorder.

Additional blood tests might include:

  • Thyroid antibodies: These tests help identify different types of autoimmune thyroid conditions. Common thyroid antibody tests include microsomal antibodies , thyroglobulin antibodies , and thyroid receptor antibodies .
  • Calcitonin: This test is used to diagnose C-cell hyperplasia and medullary thyroid cancer, both of which are rare thyroid disorders.
  • Thyroglobulin: This test is used to diagnose thyroiditis and to monitor treatment of thyroid cancer.

What Is A T4 Test

T4 Tests A Total T4 test measures the bound and free thyroxine hormone in the blood. A Free T4 measures what is not bound and able to freely enter and affect the body tissues.

What does it mean if T4 levels are abnormal? Importantly, Total T4 levels are affected by medications and medical conditions that change thyroid hormone binding proteins. Estrogen, oral contraceptive pills, pregnancy, liver disease, and hepatitis C virus infection are common causes of increased thyroid hormone binding proteins and will result in a high Total T4. Testosterone or androgens and anabolic steroids are common causes of thyroid hormone binding proteins and will result in a low Total T4.

In some circumstances, like pregnancy, a person may have normal thyroid function but Total T4 levels outside of the normal reference range. Tests measuring free T4 either a free T4 or free T4 index may more accurately reflect how the thyroid gland is functioning in these circumstances. An endocrinologist can determine when thyroid disease is present in the context of abnormal thyroid binding proteins.

Read Also: Does Graves Disease Go Away After Thyroid Removed

Controversies In Care: Universal Screening During Pregnancy

There is clear evidence that treating a pregnant woman known to be hypothyroid has important benefits14. Treatment reduces adverse pregnancy outcomes including preterm delivery or miscarriage38 and neuropsychological impairment of the offspring is associated with hypothyroidism34. At one time, studies suggested that failure to detect even subclinical hypothyroidism might have similar consequences34, 39. This led some groups to recommend that every woman be screened40. Subsequent better designed studies have not confirmed these concerns41. In fact, harm could occur when pregnant women are overtreated42. If a woman has risk factors, TSH testing is specifically recommended in early pregnancy .14 In a woman without symptoms and without risk factors, testing is discretionary.

Why You May Need A Thyroid Test

What Blood Test For Thyroid Gland Function and Cancer ...

Women of all ages are more likely than men to have low thyroid hormone levels. However, many of their symptoms are attributed to other conditions or written off as a consequence of aging.

A blood test for levels of TSH is the most sensitive test for determining whether you have hypothyroidism. Most laboratories use 0.45 5.00 mIU/L as a normal reference range for TSH. People with TSH between 5.00 and 9.99 mIU/L often have no symptoms , but some do. Another test called T4 will be done if your TSH is in this range. A low level of T4 usually means you will benefit from thyroid hormone replacement.

Many people with hypothyroidism or subclinical hypothyroidism aren’t aware anything is wrong because they haven’t been tested. The U.S. Preventive Services Task Force doesn’t recommend thyroid screening because it hasn’t found sufficient evidence that testing thyroid hormone levels in large groups of people without symptoms is cost-effective. Dr. Garber agrees, and suggests a different approachtesting asymptomatic people who are most likely to develop thyroid disease and benefit from treatment.

Treating subclinical hypothyroidism with synthetic thyroid hormone may reduce the risk of developing more serious problems like cardiovascular disease. They note that low thyroid hormone can cause a high cholesterol level and treatment with thyroid hormone may make statin therapy unnecessary.

You May Like: Thyroid Test Fasting

What Do The Results Mean

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. A TSH test does not explain why TSH levels are too high or too low. 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:

  • T4 thyroid hormone tests

Learn more about laboratory tests, reference ranges, and understanding results.

How Often Should I Get Routine Blood Work

Your doctor will typically recommend that you get routine blood work at least once a year, around the same time as your yearly physical.

But this is the bare minimum. There are several major reasons you may want to get blood tests more often than that:

  • Youre experiencing unusual, persistent symptoms. These could include anything from fatigue to abnormal weight gain to new pain.
  • You want to optimize your health. Knowing levels of various blood components, such as HDL and LDL cholesterol, can allow you to tweak your diet or fitness plan to minimize unhealthy habits . This can also maximize the nutrients you put in your body and more.
  • You want to reduce your risk of disease or complications. Regular blood tests can catch the warning signs of almost any disease early. Many heart, lung, and kidney conditions can be diagnosed using blood tests.

Talk to your doctor first if you want to get certain tests more often than once a year.

  • nutrient tests for levels of vital nutrients, such as iron or B vitamins

Some other tests that you may want include:

  • enzyme markers if youre at risk for cancer or other conditions like liver cirrhosis, stroke, or celiac disease

Read Also: Double Chin And Thyroid

T3 And T4 Interpretations

  • A normal TSH and normal T4 indicates a normally functioning thyroid gland.
  • A low TSH and high T4 generally indicates hyperthyroidism.
  • A high TSH and low T4 indicates primary hypothyroidism .
  • A low TSH and low T4 suggest secondary hypothyroidism .

For diagnostic purposes, a low T3 value accompanied by a high TSH value is considered evidence of hypothyroidism. By contrast, a low TSH value accompanied by a high T3 value is considered evidence of hyperthyroidism.

Alternative Thyroid Test #: Total Cholesterol

Thyroid Function Tests (TFTs) – Blood tests to Diagnose Thyroid Problems – T3, T4, TSH tests

This is another test youve likely had done, which is part of a standard lipid panel.

Keep in mind that we dont care about HDL vs. LDL. Ive written about why those dont matter in this post here.

We only care about total cholesterol.

In hypothyroidism, cholesterol rises because thyroid hormone is necessary to convert cholesterol into the protective steroidal hormones including pregnenolone, progesterone, and DHEA.

Total cholesterol was one of the tests used to diagnosed hypothyroidism before TSH testing was developed.

The following cholesterol levels can indicate poor thyroid function:

  • Above 230 mg/dL when not using a thyroid medication or supplement.
  • Above 200 mg/dL when using a thyroid medication or supplement.

Also Check: Will Graves Disease Go Away

How The Thyroid Works

Just as the thyroid gland communicates with other organs through the hormone it produces, the pituitary gland in the brain communicates with the thyroid through a hormone it makesthyroid-stimulating hormone, or TSH. When the pituitary senses that thyroid hormone levels are too low, it releases more TSH to coax the thyroid into action. When the thyroid is nudged by TSH, it produces thyroid hormonea large proportion of which is thyroxine and a smaller proportion triiodothyronine . The T4 is eventually converted into T3, the “active” form that is taken up by receptors in body cells.

Why Would I Need These Tests

The thyroid gland‘s hormones help control some of your body’s metabolic processes, such as heart rate, blood pressure, body temperature and weight. Too much or too little of these hormones can make you ill.

You might need thyroid tests if:

  • you have symptoms of hyperthyroidism or hypothyroidism
  • you are taking some form of thyroid hormone replacement treatment
  • you are female and being investigated for infertility

Very rarely, babies are born without a working thyroid gland. For this reason, all Australian newborns are screened for hypothyroidism with a TSH test using a drop of blood taken from a heel prick.

Don’t Miss: Can Hypothyroidism Cause Eye Floaters

Blood Test For Thyroid

Available blood test for thyroid includes the T3, T4, and TSH.

TSH TESTS

The best approach to know the thyroid capacity is to check the TSH level in thyroid test. The low level of TSH in blood test for thyroid indicates that there is excessive production of thyroid hormones whereas higher level of TSH in thyroid test indicates that there is lower production of thyroid hormones .

TSH test is recommended to know the level of production of TSH secreted by the pituitary gland and balances the production of thyroid hormones.

T4 TESTS

T4 is done to understand if the over production or under production of hormones is due to the imbalance of the pituitary gland or by the gland itself.

T4 is basically present in the blood either bounded to proteins which helps it in entering various tissues which require thyroid hormone or as free T4. Free T4 is most important during thyroid test to understand how the thyroid is working. Combining the results of TSH test with T4 thyroid test helps in precisely deciding how the thyroid gland is working.

T3 TESTS

Thyroid antibodies

How Do Tsh Values Change With Age

Thyroid Test
  • Newborns and childrenTSH and T4 levels are high in newborn babies. As the baby grows, the levels start dropping. T3 increases during the first year of life, but then it starts dropping .
  • AdolescentsTSH and T4 are decreasing and will reach expected adult levels at around 18 years old .
  • AdultsSeveral studies done on more than 10,000 non-diagnosed people show that for a healthy population TSH value is close to 1.5 mIU/L, and is higher in females than in males. 1 in 10 adults under 30 years has TSH higher than 2.5mIU/liter .
  • PregnancyTSH levels rapidly grow during pregnancy. They increase from the average 1.20 mIU/L in the first trimester to 2.12 mIU/L in the second and 3.30 mIU/L in the third trimester. The range of T3 is 1.74.3 nmol/L in second trimester and 0.43.9 nmol/L in third trimester. T4 range is 92.2252.8 nmol/L in second trimester and 108.2219.0 nmol/L in third trimester .
  • 70+4 in 10 people over 80 years have TSH higher than 2.5mIU/liter, and 1 in 10 has TSH higher than 4.5mIU/liter .

Some research suggests that the upper normal TSH reference range in people over 70 years old should be extended to 6.0 mIU/L . A study on more than 15,000 people in Scotland has confirmed that the TSH values should be reconsidered for different age intervals, and especially in people older than 70 years should not be considered out of normal ranges .

Read Also: Apple Cider Vinegar For Hypothyroidism

How Are Thyroid Tests Done

In order to properly test the hormone levels of your thyroid, a blood draw will be performed by your doctor or at a lab.

Prior to the blood draw, you will be asked to sit in a chair, roll up your sleeves and relax while a nurse or technician prepares your arm for the draw.

A band of rubber will be tightly tied around your upper arm to force the veins to swell. This makes it easier for a vein to be found so the needle can be inserted.

Having blood drawn is mostly painless, although it is possible to feel a sharp prick when the needle is inserted. This is typically a very quick sensation.

Once the blood has been fully drawn, the needle will be removed and a small bandage will be placed over your wound.

Before your tests are performed, you should tell your doctor if youre taking any medication or if you may be pregnant. This may alter the results of your test.

Patterns Of Thyroid Tests Associated With Thyroid Disease

Primary Hypothyroidism A high TSH and low thyroid hormone level can indicate primary hypothyroidism. Primary hypothyroidism occurs when the thyroid gland makes too little thyroid hormone. Symptoms of hypothyroidism can include feeling cold, constipation, weight gain, slowed thinking, and decreased energy. Causes of primary hypothyroidism include:

  • Autoimmune thyroid disease, including Hashimotos thyroiditis
  • Thyroid gland dysfunction due to a medication
  • Removal of all or part of the thyroid gland
  • Radiation injury to the thyroid
  • Excess treatment with anti-thyroid medications

Early or mild hypothyroidism may present as a persistently elevated TSH and a normal FT4 hormone level. This pattern is called subclinical hypothyroidism and your doctor may recommend treatment. Over time, untreated subclinical hypothyroidism can contribute to heart disease.

It is important to remember that normal TSH levels in older individuals are higher than the normal ranges for younger individuals.

Primary Hyperthyroidism A low TSH and a high thyroid hormone level can indicate primary hyperthyroidism. Primary hyperthyroidism occurs when the thyroid gland makes or releases too much thyroid hormone. Symptoms of hyperthyroidism can include tremors, palpitations, restlessness, feeling too warm, frequent bowel movements, disrupted sleep, and unintentional weight loss. Causes of primary hyperthyroidism include:

Also Check: Atrophic Thyroiditis

When Is A Thyroid Function Test Done

A thyroid function test is requested in a variety of situations, including if you:

  • have signs or symptoms of an underactive thyroid gland or an overactive thyroid gland
  • have signs of problems with your pituitary gland
  • are taking medicines that can affect your thyroid function, such as amiodarone and lithium
  • are pregnant
  • have infertility problems .

It is also used to monitor your response if you are taking thyroid medication, such as thyroxine.

Why Do I Need A Tsh Test

What Thyroid Blood Test for Hypothyroidism?

You may need a TSH test if you have symptoms of too much thyroid hormone in your blood , or too little thyroid hormone .

Symptoms of hyperthyroidism, also known as overactive thyroid, include:

Symptoms of hypothyroidism, also known as underactive thyroid, include:

  • Weight gain
  • Low tolerance for cold temperatures
  • Irregular menstrual periods
  • Constipation

Also Check: How To Reduce Double Chin Due To Thyroid

Drawing Blood For Thyroid Function Tests

Talk to your doctor about any medications youre taking, and tell your doctor if youre pregnant. Certain medications and being pregnant may influence your test results.

A blood draw, also known as venipuncture, is a procedure performed at a lab or a doctors office. When you arrive for the test, youll be asked to sit in a comfortable chair or lie down on a cot or gurney. If youre wearing long sleeves, youll be asked to roll up one sleeve or to remove your arm from the sleeve.

A technician or nurse will tie a band of rubber tightly around your upper arm to make the veins swell with blood. Once the technician has found an appropriate vein, theyll insert a needle under the skin and into the vein. You may feel a sharp prick when the needle punctures your skin. The technician will collect your blood in test tubes and send it to a laboratory for analysis.

When the technician has gathered the amount of blood needed for the tests, theyll withdraw the needle and place pressure on the puncture wound until the bleeding stops. The technician will then place a small bandage over the wound.

You should be able to return to your normal daily activities immediately.

How Is The Sample Collected For Testing

A blood sample is taken by a needle placed in a vein in your arm. A tourniquet is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch. The blood sample is collected in a tube, which is sent to the laboratory for analysis.

Don’t Miss: Np Thyroid Inactive Ingredients

What Are The Types Of Thyroid Disorders

    Blood tests are used to diagnose hypothyroidism or hyperthyroidism. They do not point to a specific cause. In order to determine a cause of the thyroid abnormality, the doctor will consider the patient’s history, physical examination, and medical condition. Further testing might be used to isolate an underlying cause. These tests might include more blood testing for

    • thyroid antibodies,
    • ultrasound of the thyroid gland, or
    • others.

    If thyroid cancer is suspected and surgery may be required, your physician may ask for a blood test known as thyroglobulin.

    • Thyroglobulin is a protein made only by thyroid cells.
    • If the thyroglobulin level at baseline is detectable or elevated it can be used as a tumor marker.
    • After a total thyroidectomy for cancer the level should fall to an undetectable range since the cells that make thyroglobulin have been removed.
    • If the level remains detectable after surgery, there is a possibility of thyroid tissue elsewhere in the body, and metastatic disease should be considered.
    • If the level is undetectable for a period of time after surgery and then starts to climb, a recurrence of the cancer – either at the primary site or elsewhere in the body should be considered.

    RELATED ARTICLES

    Popular Articles