Test Overview

Test Methodology

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

Test Usage

Assessment of iodine toxicity or recent exposure when a 24-hour urine cannot be collected. Monitoring iodine excretion rate as index of replacement therapy when a 24-hour urine cannot be collected.

Reference Range*

0-17 years: not established; age >=18 years: <584 mcg/g creatinine.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Administration of iodine-based contrast media and drugs containing iodine, such as amiodarone, will yield elevated results.

Test Details

Days Test Performed

Monday, Wednesday, Friday

Analytic Time

1 - 3 days

Soft Order Code




Urinary Free Iodine

+ See More



Laboratory Reference


Looking to Order a Test?

We’ve provided helpful links to make ordering easy.

Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Specimen Requirements

Offsite Collection Instructions

Due to the significant variation in the rate of secretion over the course of a day, a 24-hour collection is preferred. Collect urine in a clean, plastic container with no metal cap or glued insert and no preservative. Collection must take place prior to or 48 hours after administering gadolinium-containing contrast media. Refrigerate.


100ml Plastic Specimen Container

Normal Volume

3 mL urine

Minimum Volume

1 mL urine

Additional Information

Test sent to Mayo Clinic Laboratories.

Billing Information

Fee Codes

CPT Code

83789, 82570


55928-6, 2161-8

Have More Billing Questions?

Explore our helpful billing resources:

Billing Resources

Billing FAQ