Zinc, Urine

The Zinc, Urine test (urinary zinc; urine zinc concentration) is used to assess whole‑body zinc homeostasis and to support the evaluation of zinc deficiency, including subclinical forms, and zinc intoxication from acute or chronic exposure. It contributes to the investigation of occupational or environmental zinc exposure and can aid clinical decision‑making when interpreted alongside serum or plasma zinc measurements. Urinary zinc quantitation is useful for serial monitoring and for contexts in which blood collection is less feasible, complementing other indicators of zinc status in comprehensive evaluation.

Zinc is an essential trace element involved in hundreds of enzymatic processes, nucleic acid metabolism, protein synthesis, regulation of gene expression, cellular proliferation and differentiation, and immune function. Because body reserves are limited, systemic zinc status depends largely on dietary intake and gastrointestinal absorption, which occurs predominantly in the duodenum and jejunum. Renal handling contributes to zinc homeostasis. During deficiency, urinary zinc excretion falls substantially, and urinary concentrations can mirror overall zinc balance. In certain settings—such as pediatric testing or repeated assessments—urine zinc offers practical advantages compared with blood measurements. Severe deficiency may occur in inherited conditions such as acrodermatitis enteropathica, whereas milder, subclinical deficiency is more common among adolescents and other at‑risk groups, including pregnant or lactating individuals, patients maintained on total parenteral nutrition, and those with chronic disease. Clinical consequences include impaired skeletal growth and disturbances of immune and neurologic function. Increased urinary zinc can accompany heightened catabolism, for example with prolonged fasting. Interpretation of urinary zinc requires correlation with clinical findings and consideration of renal function, as chronic kidney disease can modify urinary excretion.