Iodine, 24 Hour Urine
Order Code: IODINEU
Epic Lab Code: LAB5791
Order Form: A-1a Miscellaneous Request or Epic Req
Commercial Mail-out Laboratory
01250 PFP
356-3527
Specimen(s):
24 Hour Urine More information
Collection Medium:
Urine - 24 hour/timed plastic urine container
Minimum:
10 mL from a 24-hour urine collection
Specimen Instructions:
Refrigerate during 24 hr collection in plastic container. Collection should be kept refrigerated for stability and submission to Core Laboratory.

Note: 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, and all subsequent urine should be collected for the next 24 hours). The last void should be included in the collection.
Turn Around Time:
3 working days upon receipt at reference laboratory
Reference Range:
0-15 years: not established
> or =16 years: 93-1125 mcg/specimen
Interpretive Data:
Daily urinary output <90 mcg/specimen suggests dietary deficiency.

Values >1000 mcg/specimen may indicate dietary excess, but more frequently suggest recent drug or contrast media exposure.
Comments:
Monitoring iodine excretion rate as an index of daily iodine replacement therapy.

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

There are no known analytic interferences with this procedure.

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

Gadolinium is known to interfere with most metals tests. If gadolinium-containing contrast media has been administered a specimen can not be collected for 48 hours.

Frozen specimens sometimes result in falsely-lowered results.
Methodology:
Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
CPT Code:
83789