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25224 Iodine Creatinine Ratio, Random Urine (ICRU)

Iodine Creatinine Ratio, Random Urine (ICRU)
Test Code: ICRUSO
Synonyms/Keywords
​Iodine Excretion, Urinary Free Iodine, Urinary Iodine, Iodine/Creatinine Ratio
Useful For

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

Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Urine (random) Plastic container​ ​3.0 mL 1.0 mL​
Collection Processing Instructions

Send aliquot in a clean, plastic aliquot container with no metal cap or glued insert. 

High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Specimen Stability Information
Specimen Type Temperature Time
​Urine ​ ​ ​Refrigerate (preferred) ​30 days
​Ambient​30 days
​Frozen​30 days
Rejection Criteria
Specimens collected and sent using metal container containers.
Interference

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

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday, Wednesday and Friday​ 1-3 day​s

ICP-MS

Enzymatic Colorimetric​ Assay

Reference Lab
Test Information

​Iodine is an essential element for thyroid hormone production.

The measurement of urinary iodine serves as an index of adequate dietary iodine intake.

Reference Range Information

0-17 years: not established

> or = 18 years: <584 mcg/g creatinine

Interpretation

​Measurement of urinary iodine excretion provides the best index of dietary iodine intake and deficiency is generally indicated when the concentrations are below 100 mcg/L. For deficiency, 10 repeat random urines are recommended.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83789 1​ Mass spect&tandem mass spect nondrg anal nes ea
​82570 ​1 ​Creatinine
Synonyms/Keywords
​Iodine Excretion, Urinary Free Iodine, Urinary Iodine, Iodine/Creatinine Ratio
Ordering Applications
Ordering Application Description
​Centricity ​Iodine Creatinine Ratio (ICRU)
​Cerner None​
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Urine (random) Plastic container​ ​3.0 mL 1.0 mL​
Collection Processing

Send aliquot in a clean, plastic aliquot container with no metal cap or glued insert. 

High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Specimen Stability Information
Specimen Type Temperature Time
​Urine ​ ​ ​Refrigerate (preferred) ​30 days
​Ambient​30 days
​Frozen​30 days
Rejection Criteria
Specimens collected and sent using metal container containers.
Interference

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

Useful For

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 Information

0-17 years: not established

> or = 18 years: <584 mcg/g creatinine

Interpretation

​Measurement of urinary iodine excretion provides the best index of dietary iodine intake and deficiency is generally indicated when the concentrations are below 100 mcg/L. For deficiency, 10 repeat random urines are recommended.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday, Wednesday and Friday​ 1-3 day​s

ICP-MS

Enzymatic Colorimetric​ Assay

Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83789 1​ Mass spect&tandem mass spect nondrg anal nes ea
​82570 ​1 ​Creatinine
For most current information refer to the Marshfield Laboratory online reference manual.