High concentrations of gadolinium and iodine are known to interfere with most metals tests. If gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.
Refrigerate specimen within 4 hours of completion of 24-hour collection.
Refrigerated (preferred) - 28 days
Ambient - 7 days
Frozen - 28 days
Inductively-coupled plasma/mass spectrometry (ICP/MS)
<4.0 µg/specimen
Reference values have not been established for patients that are <18 years of age.