Specimen:

Urine More information

Collection Medium:

Minimum:

10 mL from a 24-hour urine collection

Specimen
Instructions:

24 hour collection should be kept refrigerated for stability.

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.

Reference Range:

100-460 ug/specimen
42-350 ug/L (random collection)

Interpretive Data:

Daily urinary output <100 ug/specimen suggest dietary deficiency.

Values >460 ug/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

See Additional Information:
Urine Tests Requiring Preservatives, Refrigeration or Special Containers