The thyroid-stimulating hormone (TSH) test measures the amount of TSH in the blood. The results convey how well a person's thyroid is operation.

Doctors can employ TSH test results to diagnose thyroid disorders, such as hypothyroidism and hyperthyroidism.

The pituitary gland produces TSH, which is a hormone that stimulates the thyroid gland.

The thyroid is a butterfly-shaped gland in the throat. It produces hormones that help regulate many bodily functions, such equally metabolism, middle charge per unit, and body temperature.

This commodity describes the TSH test and results. Nosotros as well discuss what high and low TSH levels indicate and available treatments.

An infographic guide showing the ranges of TSH levels. Share on Pinterest
MNT-infographic_guide infographic by Diego Sabogal 1401179-TSH-levels-original

The normal range depends on a person's historic period and whether they are pregnant.

The ranges tend to increase as a person gets older. Research has non shown a consistent difference in TSH levels between males and females.

However, co-ordinate to the American Thyroid Association, doctors generally consider levels are within a normal range betwixt 0.4–4.0 milliunits per liter (mU/l).

The post-obit table provides estimates of TSH levels that are normal, depression (indicating hyperthyroidism), and high (indicating hypothyroidism):

Many labs use these reference values.

However, at that place is some debate near these ranges. The author of a 2016 review suggests that normal levels are more likely to fall betwixt 0.five–ii.five milli-international units (mIU) per milliliter.

Females are more likely to experience thyroid dysfunction than males. The Office on Women'due south Health reports that 1 in 8 females experience thyroid problems at some point. This includes hyperthyroidism and hypothyroidism. The take a chance of thyroid problems increases during pregnancy and around menopause.

Research does not show a consistent departure in TSH levels between males and females. However, some bear witness suggests that TSH levels are generally higher in females. For example, studies in 2020 investigating Chinese and French populations suggest that TSH levels are higher in females, simply other factors, such as age, are more than probable to affect TSH levels.

In some people, thyroid conditions are linked with sexual dysfunction. This may bear on more males than females. Co-ordinate to a 2019 written report, 59–63% of males with hypothyroidism likewise experience sexual dysfunction, compared with 22–46% of females who have hypothyroidism.

Claret TSH levels tend to increase as people get older, with evidence noting that hypothyroidism is the most common thyroid condition in people over lx and steadily increases with age.

Research involving older adults suggests that roughly 7–14% of people may have TSH levels in a higher place the upper limit of reference ranges.

Pregnancy hormones naturally increment the levels of certain thyroid hormones in the blood. This is essential for the development of the fetal brain and nervous system.

At the aforementioned time, the levels of TSH in the claret decrease. As a result, doctors employ lower reference ranges during pregnancy. The lower TSH range is decreased by around 0.four mU/l, and the upper limit reduced by approximately 0.5 mU/fifty.

Levels of TSH in the blood increase gradually during the second and third trimesters, but they remain lower than normal levels in women who are not pregnant.

Doctors carefully monitor TSH levels throughout pregnancy. Having unusually loftier or low levels can affect the risk of miscarriage and cause pregnancy-related complications, such as:

  • preeclampsia
  • premature birth
  • depression nascence weight
  • congestive heart failure

TSH levels are highest at birth and gradually subtract as a kid gets older. As such, TSH levels can vary among children. Subsequently the newborn phase, health experts may define mild hypothyroidism in children as TSH levels ranging betwixt iv.5–10 mU/50.

The following table shows TSH levels for children past age, according to an older written report using data from 512 salubrious children:

High TSH levels indicate hypothyroidism. People develop hypothyroidism when their thyroid produces low levels of hormones.

When someone'south thyroid gland does non produce enough hormones, the pituitary gland produces more TSH to compensate.

Symptoms of hypothyroidism may include:

  • fatigue
  • weight gain
  • swelling of the face and neck
  • increased sensitivity to cold temperatures
  • dry skin
  • thinning pilus
  • a slow heart rate
  • irregular or heavy menstrual periods
  • fertility problems
  • depression
  • constipation

Low TSH levels indicate hyperthyroidism. This is also known every bit an overactive thyroid.

If a person's thyroid gland is secreting levels of hormones that are besides high, the pituitary gland produces less TSH.

Symptoms of hyperthyroidism can include:

  • irregular or rapid heartbeat
  • muscle weakness
  • nervousness or irritability
  • difficulty sleeping
  • frequent bowel movements or diarrhea
  • weight loss
  • mood changes

The TSH test involves a healthcare professional drawing blood from a vein in the inner arm. They then ship the blood sample for laboratory testing.

Normally, people do not need to prepare for a TSH exam. However, if the doctor is checking the blood for more than one upshot, a person may need to fast or prepare in another way. The dr. will provide this information beforehand.

A TSH exam is often the best style to monitor thyroid role. However, if a person has abnormally loftier or depression TSH levels, the doctor may need to perform at least one other diagnostic examination to place the underlying cause. These tests wait at levels of specific thyroid hormones and antibodies.

In addition to age, sex, and pregnancy, many other factors tin as well affect TSH levels. Evidence suggests that genetic, environmental, or intrinsic factors can alter TSH levels. Some of these factors may include:

  • other weather occurring at the same fourth dimension
  • medications
  • supplements
  • ethnicity
  • diet and iodine status
  • fourth dimension of day and time of year
  • autoantibodies and heterophilic antibodies
  • smoking
  • pollutants

Doctors can care for hypothyroidism with medications, such as levothyroxine, that replace the missing thyroid hormones.

A person should take this medication one time a solar day or as prescribed. The physician will monitor how well the treatment is working by running additional blood tests every few months.

According to the Food and Drug Administration (FDA), people should take levothyroxine once a mean solar day: in the morning and on an empty stomach, at least one-half an hour before eating.

The FDA likewise recommends that a person informs their doctor if they eat soybean flour, walnuts, dietary cobweb, or cottonseed meal — these foods can bear upon how the torso processes levothyroxine. Drinking grapefruit juice may also delay the absorption of levothyroxine.

Hyperthyroidism treatments focus on reducing thyroid hormone levels to preclude long-term health complications.

A person may need to take beta-blockers and antithyroid medications.

Another effective treatment is radioiodine therapy. This involves taking a capsule or liquid that contains radioactive iodine-131, which destroys cells that produce thyroid hormones. However, people who accept radioiodine therapy may develop hypothyroidism in the future.

Surgical removal of the thyroid gland tin treat severe hyperthyroidism. Doctors often reserve this for individuals who cannot take first-line medications and severe cases of hyperthyroidism.

A TSH exam measures the amount of the hormone in the claret. Doctors can utilize the results to diagnose thyroid conditions, such as hypothyroidism and hyperthyroidism.

Normal TSH ranges can vary widely, depending on a person's age, sex, and weight. Reference TSH ranges remain controversial, but for most people, the normal range falls between 0.iv and iv.0 mU/l.

Having an overactive or underactive thyroid can cause health issues that interfere with a person's daily life. During pregnancy, unusually high or low TSH levels can pb to complications.

A doctor can provide more than data about the TSH test and interpreting the results.