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Epic Code LAB1231707 Iodine, 24 Hour, Urine

Additional Codes

Mayo Code: UIOD

Interface code: 1231707

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Assessing iodine toxicity or recent exposure in a 24-hour urine collection

 

Monitoring iodine excretion rate as index of replacement therapy

Specimen Type

Urine
Laboratory Test Directory Note:

Refrigeration during and after urine collection is the preferred means of urine preservation.


Necessary Information


24-Hour volume (in milliliters) is required.



Specimen Required


Patient Preparation:

1. High concentrations of gadolinium and iodine are known to interfere with most metal tests. If gadolinium- or iodine-containing contrast media has been administered, wait a minimum of 96 hours before starting collection.

2. If this test is used in conjunction with the (131)I uptake test, then specimen collection should begin immediately after the dose of (131)I is given (ie, the patient should void and discard urine just prior to the (131)I dose, and all subsequent urine should be collected for the next 24 hours). The last void should be included in the collection.

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic: 10-mL urine tube or clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 10 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Refrigerate specimen within 4 hours of completion of 24-hour collection.

3. See Trace Metals Analysis Specimen Collection and Transport for complete instructions.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 146 days
  Ambient  146 days
  Frozen  146 days

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.

Ambient (Plain)

OK

Refrigerate (Plain)

Preferred

Frozen (Plain)

OK

50% Acetic Acid

OK

Boric Acid

No

Diazolidinyl Urea

No

6M Hydrochloric Acid

No

6M Nitric Acid

No

Sodium Carbonate

No

Thymol

No

Toluene

No

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Day(s) Performed

Tuesday, Friday

Reference Values

0-17 years: Not established

≥18 years: 75-851 mcg/24 hour

Clinical Information

Iodine is an essential element for thyroid hormone production. The measurement of urinary iodine is preferred for assessment of toxicity, recent exposure, and monitoring iodine excretion rate as an index of replacement therapy.

Cautions

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

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.

 

World Healthcare Organization (WHO) Criteria for Assessing Iodine Status

 

Children older than 6 years old and adults

Median urinary iodine (mcg/L)

Iodine intake

Iodine status

<20

Insufficient

Severe deficiency

20-49

Insufficient

Moderate deficiency

50-99

Insufficient

Mild deficiency

100-199

Adequate

Adequate nutrition

200-299

Above requirements

May pose a slight risk of more than adequate

>299

Excessive

Risk of adverse health consequences

 

Pregnant women

Median urinary iodine (mcg/L)

Iodine intake

<150

Insufficient

150-249

Adequate

250-499

Above

requirements

>499

Excessive

 

Lactating women and children younger than 2 years old

Median urinary iodine (mcg/L)

Iodine intake

<100

Insufficient

>99

Adequate

Reporting Name

Iodine, 24 Hr, U

Method Name

Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Method Description

The metal of interest is analyzed by inductively coupled plasma mass spectrometry.(Unpublished Mayo method)

CPT Code Information

83789

LOINC Code Information

Test ID Test Order Name Order LOINC Value
UIOD Iodine, 24 Hr, U 2492-7

 

Result ID Test Result Name Result LOINC Value
9549 Iodine, 24 Hr, U 2492-7
614369 Iodine Concentration 26842-5
614423 Iodine Concentration Interpretation 77202-0
TIME5 Collection Duration 13362-9
VL23 Urine Volume 3167-4

Report Available

1 to 4 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Clinical Reference

1. Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023.

2. Knudsen N, Christiansen E, Brandt-Christensen M, et al. Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values. Eur J Clin Nutr. 2000;54(4):361-363

3. Liberman CS, Pino SC, Fang SL, et al. Circulating iodine concentrations during and after pregnancy. J Clin Endocrinol Metab. 1998;83(10):3545-3549

4. Pfeiffer CM, Sternberg MR, Schleicher RL, et al: CDC's Second National Report on Biochemical Indicators of Diet and Nutrition in the US Population is a valuable tool for researchers and policy makers. J Nutr. 2013;143(6):938S-947S

5. Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014;10(3):136-142.

 doi:10.1038/nrendo.2013.251

6. U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry: Toxicological Profile for Iodine. HHS, 2004 Accessed June 29, 2023. Available at www.atsdr.cdc.gov/ToxProfiles/tp158.pdf