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Iodine, Urine — Catheter Fluid Output

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

Measures iodine excreted in urine, which can help assess recent iodine intake and iodine availability for thyroid hormone production.

Quick summary

["Urine iodine can indicate whether iodine intake is too low, adequate, or unusually high."]

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

Key facts at a glance

LOINC
9195-9
Short code
Fluid output urine I/O cath
Synonyms
Fluid output urine I/O cath
Category
urine
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test measures iodine in urine collected as fluid output, sometimes through a urinary catheter. Urine iodine reflects how much iodine the body has recently taken in and is commonly used to evaluate iodine exposure and nutritional status.

Why might I need this test?

A clinician may order this test when iodine intake may be too low or too high, particularly in people with thyroid conditions, during pregnancy, or before using iodine supplements. It may also be used to monitor people who take large amounts of iodine or receive iodine-containing contrast treatments.

How is the test performed?

Urine is collected into a labeled container for the entire period specified by your clinician. If catheter collection is required, the catheter is used to collect the urine. The laboratory measures the iodine concentration and may account for the total amount and collection time.

How do I prepare for the test?

Follow the collection instructions exactly and record the start and end times. Tell your clinician about iodine supplements, thyroid medicines, multivitamins, and any recent iodine-containing imaging treatment, because these can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine iodine

Frequently asked questions

Does a low urine iodine result mean I have a thyroid disorder?
Not necessarily. Low urine iodine often reflects low iodine intake, while thyroid function is assessed with tests such as thyroid-stimulating hormone and free T4.
Can iodine supplements change my result?
Yes. Supplements, multivitamins, and iodine-containing medicines can substantially increase urine iodine, so disclose them to your clinician.
Why might catheter urine collection be used?
A catheter may be needed when a person cannot collect urine cleanly or completely by another method. Follow the clinician's instructions for the catheter and collection period.
  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