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How Much Blood Is Needed For A Thyroid Test

How To Order Your Lab Tests

Do You Need a Thyroid Test?

If your doctor is ordering the thyroid labs for you, be sure to request a copy so that you can see them for yourself and ensure that they are interpreted correctly.

Additionally, I have included self-order options for most of the labs discussed, in case your current doctor wont order the labs for you.

The self-order options are discounted panels that I set up with Ulta Lab and can be ordered anywhere in the U.S. You will receive a lab order that can be taken to your local lab, and the results will be sent to you electronically.

You can order each individual test that I recommend below, or you can order the entire discounted panel here.

In many cases, you can self-order the labs and then send the receipts for reimbursement to your insurance.

Now, lets take a look at each thyroid test and what they mean for your thyroid health.

What Is A Normal Range For A Thyroid Test

Laboratories use reference ranges when analysing the function of the thyroid. Typical reference ranges for a healthy individual may look like this:

  • TSH 0.27 4.2 mIU/L
  • FT4 12.0 22.0 pmol/L
  • FT3 3.1 6.8 pmol/L

Different laboratories use different reference ranges, but if your results fall outside of these parameters you could be diagnosed with hypothyroidism or hyperthyroidism.

Subclinical hypothyroidism, on the other hand, occurs when your blood TSH level is slightly raised but your FT4 is within the normal range.

Medical History And Physical Exam

If you have any signs or symptoms that suggest you might have thyroid cancer, your health care professional will want to know your complete medical history. You will be asked questions about your possible risk factors, symptoms, and any other health problems or concerns. If someone in your family has had thyroid cancer or tumors called pheochromocytomas, it is important to tell your doctor, as you might be at high risk for this disease.

Your doctor will examine you to get more information about possible signs of thyroid cancer and other health problems. During the exam, the doctor will pay special attention to the size and firmness of your thyroid and any enlarged lymph nodes in your neck.

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What Imaging Tests Do Doctors Use To Diagnose And Find The Cause Of Thyroid Disease

Your health care professional may order one or more imaging tests to diagnose and find the cause of thyroid disease. A trained technician usually does these tests in your doctors office, outpatient center, or hospital. A radiologist, a doctor who specializes in medical imaging, reviews the images and sends a report for your health care professional to discuss with you.

Thyroid ultrasound

Ultrasound of the thyroid is most often used to look for, or more closely at, thyroid nodules. Thyroid nodules are lumps in your neck. Ultrasound can help your doctor tell if the nodules are more likely to be cancerous.

For an ultrasound, you will lie on an exam table and a technician will run a device called a transducer over your neck. The transducer bounces safe, painless sound waves off your neck to make pictures of your thyroid. The ultrasound usually takes around 30 minutes.

Thyroid scan

Health care professionals use a thyroid scan to look at the size, shape, and position of the thyroid gland. This test uses a small amount of radioactive iodine to help find the cause of hyperthyroidism and check for thyroid nodules. Your health care professional may ask you to avoid foods high in iodine, such as kelp, or medicines containing iodine for a week before the test.

During the scan, you will lie on an exam table while a special camera takes pictures of your thyroid. The scan usually takes 30 minutes or less.

Radioactive iodine uptake test

Whats Included In A Thyroid Function Test

Comprehensive Thyroid Testing To Get The Answers You Need ...

A thyroid function test will usually measure your levels of:

  • T4
  • T3
  • TSH

A more advanced test will also test for the presence of any thyroid antibodies that could be causing an autoimmune disease. This might check your levels of:

  • thyroid peroxidase
  • thyroglobulin antibodies
  • TSH receptor antibodies

Its important to note that the presence of these antibodies in your blood doesnt automatically mean you have an autoimmune thyroid disease but it can indicate an increased risk of developing one in the future.

Some vitamins and minerals are essential for your thyroid to function properly like vitamin D, vitamin B12, folate , and iron. A nutrient deficiency can sometimes mimic the symptoms of a thyroid disorder. If possible, its a good idea to test your thyroid hormones and these nutrients as well.

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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.

What Is Thyroid Medication

Thyroid Hormone Treatment Levothyroxine is thestandard of care in thyroid hormone replacement therapy and treatment of hypothyroidism. Levothyroxine is equivalent to the T4 form of naturally occurring thyroid hormone and is available in generic and brand name forms.

How do I take levothyroxine? To optimize absorption of your thyroid medication, it should be taken with water at a regular time each day. Multiple medications and supplements decrease absorption of thyroid hormone and should be taken 3-4 hours apart, including calcium and iron supplements, proton pump inhibitors, soy, and multivitamins with minerals. Because of the way levothyroxine is metabolized by the body, your doctor may ask you to take an extra pill or skip a pill on some days of the week. This helps us to fine tune your medication dose for your body and should be guided by an endocrinologist.

For patients with celiac disease or gluten sensitivity, a gluten free formulation of levothyroxine is available.

Some individuals may have genetic variant that affects how the body converts T4 to T3 and these individuals may benefit from the addition of a small dose of triiodothyronine.

Liothyronine is replacement T3 thyroid hormone. This medication has a short half-life and is taken twice per day or in combination with levothyroxine. Liothyronine alone is not used for treatment of hypothyroidism long term.

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Hyperthyroidism In Pregnancy And Postpartum

Hyperthyroid patients should have appropriate specialist consultation ) when contemplating pregnancy or during pregnancy.

In the course of a normal pregnancy, TSH may be low in the first trimester, when human chorionic gonadotropin peaks. Pathological causes of low TSH in pregnancy may include multiple gestation, hyperemesis gravidarum and molar pregnancy14. In this context, a normal fT4 generally excludes hyperthyroidism14, 20. After hCG mediated hyperthyroidism, the most common pathological cause of hyperthyroidism in pregnancy is autoimmune Graves disease. Toxic multinodular goitre and toxic adenoma are less common than autoimmune causes14.

During pregnancy, if TSH is low, repeat the TSH along with fT414 . If TSH is still low and fT4 is high, refer to a specialist in endocrinology or maternal-fetal medicine . If TSH is still low but fT4 is normal, repeat testing in 4 weeks is suggested. If TSH is still low referral to a specialist is recommended.

Postpartum

Because of changes in the modulation of the immune system, there is an increased risk of thyroiditis and new presentation or relapse of Graves disease in the postpartum period14. One study found that hyperthyroidism diagnosed within 3 months of delivery was most often caused by postpartum thyroiditis while hyperthyroidism diagnosed after 6.5 months was caused by Graves disease36.

How To Keep Hypothyroidism Under Control

What Thyroid Tests Do You Need To Get?

Because youll need to take thyroid medication every day for the rest of your life, even after the right dose is found, your hormone levels will be monitored regularly to be sure that your treatment is working properly. Eventually, most people with hypothyroidism can just be seen yearly by their doctor, Doria-Medina says.

The American Thyroid Association recommends that you keep your TSH within a narrow range of 0.5 to 2.5 mU/L, but dont be alarmed if your test results vary a little. Some variation is normal because your pituitary gland sends out TSH in pulses, not a steady stream. Also, factors like the time of day youre tested can make a difference. TSH levels are likely to be higher at night and lower during the day. Some people, including those who are pregnant or those with a history of thyroid cancer, have different TSH goals. Talk to your doctor about the target TSH range thats right for you.

If you have new or worsening symptoms or your health status changes such as if you become pregnant, go through menopause, or are given another medicine that can interfere with the absorption of your thyroid hormones, such as anticonvulsants, certain antacids, or iron or calcium supplements you should see your doctor and have your blood tested again, even if its ahead of schedule.

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What Other Tests May Be Ordered In Addition To A Thyroid Panel

Blood tests that may be performed in addition to a thyroid panel may include:

  • Thyroid antibodies – to help diagnose autoimmune thyroid disease and distinguish it from other thyroid conditions
  • Calcitonin – to help diagnose C-cell hyperplasia and medullary thyroid cancer
  • Thyroglobulin – primarily to monitor treatment and recurrence of thyroid cancer
  • Thyroxine-binding globulin – to evaluate patients with abnormal T4 and T3 levels

How Do You Find Out If You Have Thyroid Problems

Many Australians live with a thyroid condition, with 4% having an undiagnosed thyroid disorder. Symptoms can range from low energy, insomnia, depression and unexplained weight gain.

Thyroid Function Blood Testing can help check your thyroid gland is working properly. With a simple blood test, you can check your Thyroid’s hormone levels which is all that is needed for you to find out if you have a Thyroid problem like hypothyroidism.

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The Thyroid Screening Test

The thyroid stimulating hormone, or TSH test, is used as a screening test for thyroid disease, as well as a test for monitoring the correct dose of medication needed for an individual.

TSH is a pituitary hormone that responds to low/high amounts of circulating thyroid hormone. If youre new to thyroid lab testing, it may seem counterintuitive, but an elevated TSH means that you do not have enough thyroid hormone on board and that you are hypothyroid. This is because the TSH hormone senses low thyroid levels and is released when there is a lack of it, in an effort to get the body to make more.

In advanced cases of Hashimotos and primary hypothyroidism, this lab test will be elevated. In the case of Graves disease and hyperthyroidism, TSH levels will be low. People with Hashimotos and mild or central hypothyroidism, may have a normal reading on this test.

If youve been a thyroid patient for a while, youre probably thinking to yourself, Well, of course, doesnt everyone know that? and I have to warn you Ive unfortunately seen physicians who have mistakenly thought that a low TSH meant one had an underactive thyroid, and a high TSH, an overactive thyroid putting their patients in really dangerous situations by over or under medicating them!

Thus, many physicians may miss the patients who are showing an elevated TSH. This is one reason why patients should always ask their physicians for a copy of any lab results.

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What Does The Tsh Test Involve

How Much Is A Thyroid Blood Test

The TSH blood test is often administered as part of a panel of blood tests in conjunction with an annual health exam. The test determines how well your thyroid is working by measuring the amount of thyroid-stimulating hormone in your blood. Its a non-fasting blood test, meaning you dont have to do anything special to prepare.

Physicians should take a TSH blood sample for thyroid patients every four to eight weeks after their initial diagnosis. TheATA recommends TSH testing every six to 12 months while youre on a stable medication dose and more often if your dose has changed.

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Is There Anything Else I Need To Know About A Thyroxine Test

Thyroid changes can happen during pregnancy. Although it is not common, some women can develop thyroid disease during pregnancy. Hyperthyroidism happens in about 0.1% to 0.4% of pregnancies, while hypothyroidism happens in approximately 2.5% of 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. Also, 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.

What Are The Different Types Of Thyroid Blood Tests

Thyroid function tests are a set of blood tests used to measure how well your thyroid gland is working. They help detect an overactive or underactive thyroid gland and also give hints about other related conditions. There are three main types of thyroid blood tests:

  • TSH test: A thyroid stimulating hormone is not released by the thyroid gland. It is made in the pituitary gland in the brain. When thyroid levels in your body get low, the pituitary gland makes more TSH which serves as a signal for the thyroid gland to compensate and release more thyroid hormones. When thyroid levels are high, the pituitary gland makes less TSH. Hence, the TSH levels that are too high or too low can tell if your thyroid is working well.
  • T4 test: Measures the blood level of the hormone T4 .
  • T3 test: Measures the other major thyroid hormone T3 in the blood.

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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 Hashimoto’s 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:

Fasting And Thyroid Test Results

What Thyroid Blood Test for Hypothyroidism?

Studies have shown that time of day and fasting can affect your results. If you test in the early morning after overnight fasting, the results may show higher levels. This is compared to tests done later in the day with no fasting.

That can be a problem if you have subclinical hypothyroidism. This is when you have a mildly elevated TSH and normal free T4, but no symptoms. Free T4 is the active form of T4.

This condition is diagnosed and monitored based solely on TSH. T4 and T3 levels are usually normal.

If you get your blood test in the afternoon when you have not been fasting, your TSH levels will be lower. Because of this, your subclinical hypothyroidism may be missed.

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Thyroid Test Kit Fast Facts

  • At-home thyroid test kits are considered very accurate, but you should make sure you are purchasing a CLIA- and CAP-certified test through a reputable provider.
  • Popular thyroid kits offer testing for several biomarkers, including free thyroxine , free triiodothyronine , thyroid stimulating hormone , and thyroid peroxidase antibodies , in addition to others.
  • At-home test kits are an inexpensive and easy way to learn more about your thyroid health or monitor your thyroid health without going to see a doctor for regular testing.
  • Most test kits will provide your test results along with a basic analysis of results, but its important to see your healthcare provider for in-depth analysis, diagnosis, and proper treatment.
  • You should never self-medicate or change a prescription or medical plan based off of at-home test kit results without speaking with your doctor first.

What Initial Tests Are Used To Diagnose Hypothyroidism In Dogs

Thyroid hormones have widespread effects on the body, and are involved in the metabolism of food as well as the daily metabolic functions of most of the body’s tissues and organs. Therefore, the effects of decreased thyroid hormone concentrations may be seen in many initial blood and urine screening tests. Changes in the initial screening tests help identify the presence of hypothyroidism, and may uncover other conditions, some of which may be related to decreased thyroid hormone production while others may indicate other, non-related problems.

Complete blood count . The white blood cells, red blood cells, and platelets are evaluated in this test. Occasionally a mild anemia may be seen with hypothyroidism because thyroid hormone is required for optimal red blood cell production. Changes in the appearance of the individual red blood cells may also be noted. While target cells are not specific for the diagnosis of hypothyroidism, their presence is supportive of the diagnosis.

Hypothyroidism may result in compromised immune function, so occasionally an increased number of white blood cells may be found because of some concurrent inflammatory or infectious condition.

“The main feature noted on the serum biochemistry profile in approximately 75% of hypothyroid dogs is an increase in cholesterol.”

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