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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

​Monitoring iodine excretion rate as an index of daily iodine replacement therapy. 

Correlating total body iodine load with (131)I uptake studies in assessing thryoid function.

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
​2.0 mL random urine in a plastic container.  Send aliquot in a clean, plastic aliquot container with no metal cap or glued insert.  Contact Marshfield Labs' Customer Service for more information.
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​Refrigerate ​Up to 30 days
Rejection Criteria
Specimens collected and sent using metal container containers.
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday, Tuesday, Wednesday and Friday​ 1 day​ ICP-MS and Enzymatic Colorimetric​
Reference Lab
Mayo Clinic Laboratories
Reference Range Information
Interpretive report
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
​2.0 mL random urine in a plastic container.  Send aliquot in a clean, plastic aliquot container with no metal cap or glued insert.  Contact Marshfield Labs' Customer Service for more information.
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​Refrigerate ​Up to 30 days
Rejection Criteria
Specimens collected and sent using metal container containers.
Useful For

​Monitoring iodine excretion rate as an index of daily iodine replacement therapy. 

Correlating total body iodine load with (131)I uptake studies in assessing thryoid function.

Reference Range Information
Interpretive report
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday, Tuesday, Wednesday and Friday​ 1 day​ ICP-MS and Enzymatic Colorimetric​
Reference Lab
Mayo Clinic Laboratories
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.