Skip to content

Iodine concentration in 24-hour urine

Published: August 9, 2026Updated: August 16, 2026

This test measures how much iodine your body excretes in urine over a full day. It helps assess iodine status, especially in people at risk of iodine deficiency.

Quick summary

["This test helps check if you have enough iodine in your body over time."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
33122-3
Short code
GA from IOD.Mayden82
Synonyms
GA from IOD.Mayden82
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-iod-mayden
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why is this test done?

Your healthcare provider may order this test if you have symptoms of iodine deficiency (like fatigue or hair loss), live in an area with low iodine in food, or are taking certain medications that may affect iodine levels. It’s also used in screening programs for populations at higher risk.

What does the test involve?

You’ll collect all urine you pass over a 24-hour period in a special container. The sample is then sent to a lab for analysis to measure iodine content.

How is the test prepared?

Follow your provider’s instructions carefully. Typically, you’ll start collecting urine at a specific time (often midnight) and continue until the next day’s midnight. Drink plenty of water to help flush out iodine naturally. Avoid foods or supplements with iodine (like some iodized salts or certain medications) unless instructed otherwise.

What are the results interpreted as?

Results are compared to reference ranges for iodine excretion in urine. Lower-than-expected levels may indicate iodine deficiency, while higher levels could suggest overconsumption or certain medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Iodine

Frequently asked questions

How often should I get this test?
Your provider will determine the frequency based on your health needs. It’s often done as part of routine screening or monitoring for iodine status.
What do I do if my results are abnormal?
If your results are low, your provider may recommend dietary changes (like iodine-rich foods) or supplements under medical supervision. If high, they may investigate other causes like medication use or medical conditions.
Does this test hurt or cause discomfort?
No discomfort is expected. The only effort required is collecting urine over 24 hours, which is similar to a standard urine sample collection.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy