Iodine Deficiency Test: Best Options Reviewed

Are you worried you may have an iodine deficiency?

If you are always tired, gaining weight unexpectedly, and having trouble concentrating, you may have low levels of iodine to blame.

While there are many ways to test for iodine deficiency, not all tests are accurate. Read below to see what the most common test is and whether it is a good option for you. The answer might surprise you!

Why is Iodine Important?

Iodine is important for the functioning of the thyroid gland. This small butterfly-shaped gland lives at the front of your throat and is responsible for regulating metabolism, brain development, muscle control, mood, and heart health.

Iodine allows the thyroid gland to produce thyroid hormones. Iodine is absorbed by the thyroid gland and combines with an amino acid called tyrosine to create the hormones T1, T2, T3, or T4.

Iodine is also known for its antimicrobial properties. You may have an iodine ointment in your first aid kit for cuts and scrapes, although it has become less popular because it stains the skin a bright orange color.

Too much or too little iodine isn’t good for your body. While iodine deficiency is more common, too much iodine can also happen and lead to symptoms that look a lot like an iodine deficiency. This is why it is important to have an iodine test done before taking any supplements.

What are the Symptoms of Iodine Deficiency?

Symptoms of iodine deficiency tend to look very similar to hypothyroidism, a condition where the thyroid doesn’t produce enough thyroid hormones. This is because iodine deficiency eventually leads to hypothyroidism if left unchecked.

Symptoms of iodine deficiency include:

  • Goiter (swelling of the thyroid gland)
  • Slow growth and development in children
  • Fatigue
  • Poor memory
  • Trouble concentrating
  • Unintentional weight gain
  • Hypothyroidism

How do You Test for Iodine Deficiency?

There are five types of iodine deficiency tests available today. Each one has varying levels of effectiveness, and the tests used by doctors are not always the best option for determining an iodine deficiency. The different types of tests available are:

  1. Urine Test
  2. Blood Test
  3. Loading Test
  4. Patch Test

1. Urine Test for Iodine Deficiency

The urine test for iodine deficiency is probably the most common in doctors’ offices. Fasting is not required for this test and it only requires one sample, making it relatively easy to do.

That being said, urine tests are not the most accurate. Results can be affected by dehydration or over-hydration. It is also hard to determine an iodine deficiency from one urine sample because urine iodine levels can change throughout the day.

Urine iodine tests can also be a problem because they only reflect how much iodine has been eaten recently. It doesn’t account for iodine stored in they thyroid gland or elsewhere in the body, which is an important factor to take into account.

2. Blood Test for Iodine Deficiency

Blood tests for iodine deficiency are available but are not done very often. This is because they are not a good accurate measure of iodine levels throughout the body.

There is not a lot of iodine floating around in the blood stream – most iodine is stored in the thyroid gland and is used to make thyroid hormones like T3 and T4. Iodine blood tests will not account for stored iodine or iodine present in thyroid hormones, leading to inaccurate results.

3. Loading Test for Iodine Deficiency

The loading test for iodine deficiency is more expensive than the previous two options but is more accurate. This is because it measures the amount of iodine you eliminate in your urine over a 24-hour period.

Before the test, a 50mg tablet of iodine is taken. Afterwards, you’ll collect a sample every time you urinate for the next 24 hours. This does not need to be done in a doctor’s office – samples are collected at home and either dropped off at your doctor’s office or mailed off to a lab.

If you are not deficient in iodine, you’ll excrete about 90% of the iodine you took within the 24 hours. Less than this can indicate a deficiency because your body is absorbing more of the iodine than usual. The lower the excretion rate, the more severe your iodine deficiency.

While it is more accurate, this test is less convenient than a one-time sample and can be challenging for people with busy schedules.

4. Patch Test for Iodine Deficiency

The patch test is easily the least expensive and easiest option to see if you have an iodine deficiency. It can even be done at home, although the results are not as accurate as other methods.

To do the patch test, use a 2% iodine solution to draw a 2 inch by 2 inch square on your forearm. If you are deficient in iodine, your body will absorb the solution and the patch will begin to fade in color within 24 hours.

If you are severely deficient, the patch will disappear completely in 12 hours or less.

If you decide to try the patch test at home, make sure to have the results confirmed by a more reliable test. It’s not a good idea to start an iodine supplement based solely on the patch test without speaking with a doctor first.

Takeaway Notes

  • Iodine has many functions in the body, the most well-known being its role in thyroid health.
  • Iodine deficiencies can lead to fatigue, trouble with memory, stunted growth, and hypothyroidism.
  • Ways to test for iodine deficiency include blood tests, urine tests, and patch tests.
Kelli Yates
Kelli Yates
Kelli Yates is a health and nutrition writer, dietetics student, and co-host and creator of The Nutrition Nerds Podcast. In her spare time she teaches the free class Well-Fed Survival: Eating Healthy After A Disaster, which helps people build nutritious emergency food supplies and prepare for natural disasters.
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