Total plasma zinc:
Zinc can be measured using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). It is important to mention that specimens for trace metal testing need to be collected in metal-free specimen containers/tubes. The patient should also not have received gadolinium, iodine, or barium-containing contrast material within the past 96 hours. These metal-based contrast agents are known to interfere with the mass spectrometry used for analysis. Collection of blood and plasma should not be done using povidone-iodine disinfectants. Wooden sticks, utensils, or pipettes should also not be used to remove clots, as these can introduce trace metals.
Urine zinc:
Although fecal excretion of zinc is the dominant route of elimination, urine testing for zinc is common. Elevated urine zinc with low serum zinc may indicate hepatic cirrhosis, neoplastic disease, or increased catabolism. In contrast, elevated urine zinc with normal or elevated serum zinc suggests excess dietary sources (usually vitamins).
Low urine zinc with low serum zinc is likely due to dietary deficiency or increased loss, as occurs in burn patients or those with hypermotility of the GI tract.
