Update Type: Replacement Test
Test Updated: 10/13/2021
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 Set Up
Tuesday, Friday
Analytic Time

3 - 6 days

Soft Order Code
  • Urinary Free Iodine
Reference Laboratory
Special Testing
Specimen Requirements
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.

Normal Volume
3 mL urine
Minimum Volume
2 mL urine
Storage Temperature
Refrigerated (preferred): 30 days. Room Temperature: 14 days. Frozen: 30 days.
Additional Information

Test sent to Mayo Clinic Laboratories.

CPT Code
83789, 82570
Fee Code
AA492, AA180
55928-6, 2161-8