Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Zinc is an essential trace element and a cofactor for over 300 enzymes, involved in energy and nucleic acid metabolism, immune function, wound healing and tissue repair. Body zinc status is assessed by measurement of zinc in serum, which is useful in the diagnosis and monitoring of zinc deficiency and excess. Several factors can affect serum zinc concentration, independent of zinc status, including serum albumin, diurnal variation, and time of sampling in relation to meals. Zinc is a negative acute phase reactant; serum zinc should be measured two weeks after the acute phase has resolved.
Specimen container paediatric:
Serum trace element tube; Navy blue top with red-striped label – preferred sample
White top plain tube (glass)
Specimen container adult:
Serum trace element tubeNavy blue top with red-striped label
Available on request from Blood Sciences reception at both Freeman and RVI sites
Minimum volume paediatric:
1 mL blood
Minimum volume adult:
1 mL blood
Special requirements:
Grossly haemolysed samples are unsuitable for analysis. Transport to laboratory immediately for rapid separation of serum from red blood cells.
Sample stability:
After separation from red cells, serum is stable for one month when stored at 4°C. Samples may be stored indefinitely at -20°C.
Transport requirements:
Ambient temperature.
Freq analysis:
Assay performed weekly.
Quality assurance:
Trace Element Quality Assurance Scheme (TEQAS) for Trace Elements
Interpretation:
Low serum zinc:
Inadequate dietary intake/parenteral nutrition
High levels of copper or iron in the diet (interfere with zinc absorption)
Loss via open wounds/burns, gastrointestinal tract
Crohn’s disease, ulcerative colitis, regional enteritis, sprue, intestinal bypass, malignancy, and increased catabolism by anabolic steroids
Anorexia and starvation
High serum zinc:
Megadoses of supplements
Not usually of clinical concern
Reference ranges:
| Age | Zinc (µmol/L) |
| <6 months |
5.0 – 21.5 |
| 6 months to18 years |
9.8 – 19.0 |
| 19 years to 64 years (female) |
9.6 – 20.5 |
| 19 years to 64 years (male) |
10.1 – 20.2 |
| >64 years (female) |
9.2 – 19.2 |
| >64 years (male) |
8.0 – 20.0 |
Factors affecting result:
Haemolysis ++
Heparin may contain zinc.
EDTA leaches zinc from rbc into plasma.
Rubber stoppers/caps release significant amounts of zinc.
Gel separation systems release zinc.
Other info:
Assay performed by ICP-MS in collision mode.