Iodine, 24 Hour, Urine
Use
Measurement of urinary iodine excretion in a 24‑hour urine collection is useful for assessing iodine toxicity or recent exposure and for monitoring iodine excretion rate as an index of replacement therapy.
Special Instructions
If gadolinium‑ or iodine‑containing contrast media have been administered, do not collect specimen for at least 96 hours. When used in conjunction with an (131)I uptake test, collection should begin immediately after dosing; discard prior void and include last void. See Metals Analysis Specimen Collection and Transport and Urine Preservatives‑Collection and Transportation for 24‑Hour Urine Specimens for complete instructions.
Limitations
Administration of iodine‑based contrast media and iodine‑containing drugs (e.g., amiodarone) can yield elevated results. Interference from gadolinium‑ or iodine‑containing contrast media for at least 96 hours post‑administration. Only based on ICP‑MS performance characteristics in a CLIA‑compliant Mayo Clinic lab; not FDA cleared.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 2492-7
- 2492-7
- 13362-9
- 3167-4
- 26842-5
- 77202-0
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL
Minimum Volume
0.3 mL
Container
Clean plastic aliquot container or 10‑mL plastic urine tube; no metal cap or glued insert
Collection Instructions
Collect urine for 24 hours; refrigerate within 4 hours of completion; if using with (131)I uptake, begin after dose, discard prior void, include last void.
Patient Preparation
Avoid specimen collection for 96 hours after administration of gadolinium‑ or iodine‑containing contrast media.
Storage Instructions
Refrigerate within 4 hours of collection; submission refrigerated preferred.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | OK up to 28 days |
| Refrigerated | Preferred up to 28 days |
| Frozen | OK up to 28 days |