Quick Facts
- Sample: 24-hour urine collection
- Fasting: Not required
- Turn-around: 3-5 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Accurate assessment of your body's iodine status over 24 hours
- Early detection of iodine deficiency or excess affecting thyroid function
- No doctor visit required for direct-to-consumer testing
- Support thyroid health through informed dietary and supplement decisions
- Essential monitoring for pregnancy, dietary restrictions, or thyroid conditions
Who Is This Test For?
- Pregnant women ensuring adequate iodine for fetal development
- People with thyroid disorders monitoring iodine status
- Vegans and vegetarians with limited iodized salt intake
- Individuals on restricted diets checking nutritional adequacy
- Those with unexplained fatigue or weight changes
- People concerned about environmental or occupational iodine exposure
How It Works – Just 3 Steps
- Order your test online and visit your local lab to receive collection kit
- Collect all urine for 24 hours following kit instructions precisely
- Return your sample to the lab and receive confidential results in 3-5 days
FAQ
What does this test measure? Total iodine excreted in urine over 24 hours, indicating recent intake and body status.
How accurate is the 24-hour collection? It's the gold standard for assessing iodine status, more accurate than spot urine tests.
Can I take supplements before testing? Avoid iodine supplements and iodine-rich foods 2-5 days before collection for accuracy.
What if I miss some urine during collection? The test may be inaccurate; you'll need to repeat with complete 24-hour collection.
Are results immediately actionable? Results should be interpreted by a healthcare provider for personalized recommendations.
How does this differ from blood iodine tests? Urine testing better reflects recent iodine intake and is the preferred assessment method.
More Details
What is the purpose of this test?
The 24-hour Iodine Urine Test measures total iodine excretion to assess your body's iodine status. Iodine is essential for thyroid hormone production, which regulates metabolism, growth, and development (Mayo Clinic 2025). This comprehensive assessment helps identify both deficiency and excess, supporting optimal thyroid function and overall health.
Who would benefit from this test?
This test is particularly valuable for pregnant women, as iodine deficiency can cause developmental issues in babies (CDC 2024). People with thyroid disorders, those following restrictive diets, and individuals concerned about nutritional adequacy also benefit. Additionally, it's useful for monitoring supplementation effectiveness and assessing environmental exposure risks.
When should I order an Iodine Urine Test, 24-Hour?
Consider testing if you experience unexplained fatigue, weight changes, or thyroid-related symptoms like goiter. Pregnant women should test to ensure adequate iodine for fetal development. Those on vegan diets, restrictive eating plans, or living in areas with limited iodized salt access should also consider testing (NIH 2024).
How do I interpret the results?
Less than 100 mcg/L
- What it means: Deficient
- Typical action: Increase iodine intake through diet or supplements
100–199 mcg/L
- What it means: Adequate
- Typical action: Maintain current iodine intake
200–299 mcg/L
- What it means: Above requirements
- Typical action: Monitor intake, may reduce if excessive
300 mcg/L or higher
- What it means: Excessive
- Typical action: Reduce iodine sources, consult healthcare provider
About 11.1% of Americans have moderate iodine deficiency, with higher rates in women of reproductive age (CDC 2024).
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
Avoid iodine-rich foods like seaweed, iodized salt, and seafood for 2-5 days before testing. Stop iodine supplements and certain medications like amiodarone if medically appropriate. Don't collect during menstruation to avoid contamination. Begin collection after discarding your first morning urine (Mayo Clinic 2025).
How often should I get tested?
- General health monitoring: Every 1–2 years
- Thyroid disorder management: Every 6–12 months
- Pregnancy or planning pregnancy: Before conception and each trimester
- Dietary restriction changes: 3–6 months after changes
- Supplementation monitoring: 3–6 months after starting
Why early detection matters
Iodine deficiency can lead to goiter, hypothyroidism, and impaired cognitive development in children. During pregnancy, deficiency increases risks of miscarriage, stillbirth, and developmental delays (WHO 2023). Early detection allows for timely intervention through dietary changes or supplementation, preventing serious health complications.
Related tests you may consider
Thyroid Panel with TSH - provides comprehensive thyroid function assessment alongside iodine testing.
Thyroglobulin Antibodies Blood Test Panel - help detect autoimmune thyroid conditions affecting iodine utilization.
Selenium Blood Test - evaluates another essential mineral for thyroid hormone metabolism and may be useful for unexplained thyroid symptoms.
