Scottish Trace Element and Micronutrient Reference Laboratory

Scotland's specialised laboratory for trace elements and vitamins in health and disease

Zinc (Zn)

Trace Elements

Vitamins

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Zinc is an essential element of established importance in humans: numerous enzymes are zinc metalloproteins which control several stages of both protein and nucleic acid synthesis. Severe deficiency of zinc occurs in acrodermatitis enteropathica, an inherited defect in which zinc absorption from the intestine is impaired. It results in retarded growth, hypogonadism, skin & ophthalmic lesions, and a deficiency in cell-mediated immunity.

Determination of plasma zinc concentration is by far the most commonly used procedure for investigation of suspected zinc deficiency. However, the interpretation of small changes in the concentrations observed in respect to a reference population is complicated by several factors which affect plasma zinc concentration independently of zinc status. These include the concentration of plasma albumin, diurnal variation, the time of sampling in relation to meals, and a non-specific decrease following the acute phase response. In this country significant zinc deficiency is most likely to occur in patients on TPN feeding, and those with malabsorption, burns, or prolonged diarrhea. This can result in poor appetite, delayed wound healing, dermatitis, mental lethargy, and growth retardation.

Increased urinary zinc may be due to muscle breakdown and/or infusion of chelating agents. Such factors make the use of urine zinc unreliable as a test for zinc deficiency in hospital practice, although urinary excretion is reported to be lower than normal in chronic zinc deficiency.

More on Zinc

Sample Requirements and Reference Values

Karen Elliot analysing plasma samples for copper and zinc by inductively-coupled plasma atomic emission spectrometry

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