BiomarkersIodine (serum)

Minerals

Iodine (serum)

Iodine in your blood, needed for thyroid hormone

On your report it may say: Serum iodide

Iodine is needed to make thyroid hormone. Serum iodine is a specialised test and isn't interchangeable with urinary iodine; most people in India get enough iodine from iodised salt.

Updated 2026-10-26

Typical ranges · µg/L

Low below 52
In range 52–109
High 109+

Recent iodine-containing contrast scans or supplements raise the result.

Ranges vary by lab, age and sex. The range printed on your report applies.

If it's low

Iodine intake may be low.

Common causes

  • Not using iodised salt
  • Very low dairy and seafood intake

What you might notice

  • Goitre (swelling in the neck)
  • Tiredness

If it's high

Usually recent iodine exposure from contrast dye, kelp or supplements.

Common causes

  • Contrast scans
  • Kelp or seaweed supplements
  • Iodine supplements

What you might notice

  • Thyroid changes in sensitive people

Testing

Who should test
Only when a doctor needs to assess iodine specifically.
How to prepare
Avoid iodine supplements and seafood before testing if asked.
When to retest
As your doctor advises.

What can help

Food sources

Iodised saltDairyEggsSeafood

Talk to your doctor before taking iodine if you have a thyroid condition.

Common questions

Do I need iodine if I use iodised salt?

Usually not.

Serum or urine?

Urinary iodine is more commonly used to judge intake.

Explore further

When to take them

Sources

  1. NIH Office of Dietary Supplements: Iodine fact sheet for health professionals

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For general education only, not medical advice. Ranges shown are typical for adults; the range printed on your lab report applies. Talk to a qualified doctor about your results.