Iodine (Urine)
Measures urinary iodine levels to assess iodine intake and nutritional status, particularly important for thyroid hormone production and overall metabolic health.
Select Lab Partner
What this test measures
The urine iodine test measures the amount of iodine excreted in the urine over a 24-hour period or in a single spot sample. Iodine is an essential trace element that the body cannot produce on its own, requiring dietary intake through foods like seafood, dairy products, iodized salt, and certain vegetables. About 90% of ingested iodine is excreted through the kidneys, making urinary iodine concentration a reliable indicator of recent iodine intake and overall iodine status.
Iodine is crucial for the production of thyroid hormones --- thyroxine (T4) and triiodothyronine (T3) --- which regulate metabolism, protein synthesis, and cellular energy production throughout the body. These hormones are particularly important during pregnancy and early development, as they support proper growth and maturation of organs, especially the brain and nervous system. The test helps healthcare providers assess whether individuals are getting adequate iodine from their diet and can guide decisions about iodine supplementation when necessary.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals with thyroid disorders or symptoms of thyroid dysfunction, including unexplained fatigue, weight changes, or temperature intolerance, may benefit from iodine assessment to determine if iodine deficiency contributes to their condition.
- Pregnant and breastfeeding women who require higher iodine intake should consider testing, as maternal iodine deficiency can impact fetal brain development and increase the risk of developmental delays in children.
- Those following restrictive diets, including vegans, vegetarians, or individuals avoiding processed foods, may have lower iodine intake since plant-based foods typically contain less iodine than seafood and dairy products.
- People living in areas with iodine-depleted soil or those who primarily consume locally grown foods from inland regions may need monitoring, as geographic variations in soil iodine content can affect dietary intake.
- Individuals taking medications that can interfere with iodine metabolism or those with a history of exposure to iodine-containing contrast agents may benefit from monitoring to ensure proper iodine balance.
What to expect
Preparation
No special preparation is typically required for a spot urine test. Avoid iodine-containing contrast agents or supplements for at least 96 hours before testing if possible.
Sample Type
Collection involves providing either a single spot urine sample or a complete 24-hour urine collection, depending on the specific test ordered.
Collection
For spot urine collection, patients provide a single urine sample at the lab. For 24-hour collection, detailed instructions are provided for collecting all urine over a full day period.
Turnaround
Results are typically available within 2-5 business days after sample collection and processing.
Understanding your results
Results are interpreted based on World Health Organization guidelines that consider adequate iodine intake as urinary concentrations of 100-199 mcg/L for adults and children, with values below 100 mcg/L indicating insufficient intake. Higher levels may suggest excessive iodine intake, while lower levels may indicate deficiency.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 100-199 mcg/L | WHO-recommended range indicating adequate iodine intake for most healthy adults |
| Pregnant Women | 150-249 mcg/L | Higher range reflects increased iodine needs during pregnancy for fetal development |
| Lactating Women | >100 mcg/L | Minimum threshold for adequate iodine status during breastfeeding |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Low urinary iodine levels suggest insufficient iodine intake and may be associated with mild deficiency (50-99 mcg/L), moderate deficiency (20-49 mcg/L), or severe deficiency (less than 20 mcg/L). Iodine deficiency can lead to hypothyroidism, characterized by symptoms such as fatigue, weight gain, cold intolerance, and in severe cases, goiter (enlarged thyroid gland). Prolonged iodine deficiency is particularly concerning during pregnancy and early childhood, as it represents the most common preventable cause of intellectual disability worldwide and can affect cognitive development.
What does a “High” result mean?
Elevated urinary iodine levels may indicate excessive iodine intake, which can potentially lead to thyroid dysfunction including both hyperthyroidism and hypothyroidism. High iodine exposure may cause iodine-induced hyperthyroidism (IIH), particularly in individuals with pre-existing thyroid conditions, leading to symptoms such as rapid heart rate, weight loss, muscle weakness, and skin warmth. Excessive iodine intake often results from supplements, iodine-rich foods like seaweed, or medical procedures involving iodine contrast agents.
Privacy & confidentiality
All test results are kept strictly confidential and protected under HIPAA regulations. Results are not shared with insurance companies, employers, or added to your medical records without your explicit consent, ensuring your privacy throughout the testing process.
Frequently asked questions
Related tests
TSH
$39Evaluates thyroid function and can help assess the clinical significance of iodine levels
View TestBasic Thyroid Panel
$59Comprehensive thyroid assessment to evaluate how iodine status affects thyroid hormone production
View TestComprehensive Thyroid Panel
$129Complete thyroid evaluation including antibodies to assess autoimmune thyroid conditions that may be affected by iodine intake
View TestUrinalysis
$29Basic urine testing to ensure kidney function is normal for proper iodine excretion interpretation
View TestRelated conditions
CPT Code: 84525
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
Select Lab Partner
Not sure if this is the right test? Contact our care team for guidance.