Zinc

Also Known As

This article was last reviewed on

1 February 2022.

This article waslast modified on 1 February 2022.

At a Glance

Why Get Tested?

To measure the amount of zinc in the blood (or sometimes urine) in order to identify/diagnose deficiency or to monitor response to supplementation

When To Get Tested?

When you have symptoms that may suggest zinc deficiency e.g hair loss, poor wound healing

Sample Required?

A blood sample is taken from a vein in the arm and/or a urine sample (preferably 24h collection) is provided.

Test Preparation Needed?

Haemolysis (red blood cell rupture that occurs when the sample is taken) should be avoided as red blood cells contain ~10x the amount of zinc than that of plasma/serum. Fasting samples may be preferred as plasma/serum zinc concentrations have been shown to decrease after eating meals.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

This test measures the amount of zinc in the blood (or sometimes urine). Zinc is an essential trace element with important functions throughout the body. Zinc is important for protein synthesis, enzyme function and plays a structural role in proteins and nucleic acids.

Zinc is a component of many high protein foods such as meat, fish and dairy products. It is present in vegetables and grains but the bioavailability is reduced because dietary fibres can inhibit its absorption.

Approximately 20-30% of ingested zinc is absorbed in the small intestine. Zinc is transported in the plasma bound to albumin (~80%) and α2-macroglobulin (~20%). The major route of zinc excretion is via the faeces with little being lost in urine, sweat and other bodily secretions.

Zinc is present in many tissues throughout the body but is not stored at any particular site. Therefore in anabolic states where zinc requirements exceed intake, or where poor absorption occurs, zinc deficiency can result.

Zinc deficiency can present clinically with hair loss, poor wound healing, dermatitis and impaired immune function. In children zinc deficiency can cause growth retardation.

Conditions commonly associated with zinc deficiency include: alcoholism, pregnancy & burns.

Acrodermatitis enteropathica is an inherited disorder of zinc metabolism/absorption. Zinc deficiency can be treated by supplementation and leads to improvement of clinical symptoms.

Common Questions

How is it used?

Zinc testing is used to investigate for zinc deficiency. It is also useful for monitoring a person who is being nutritionally supplemented to ensure adequate concentrations are achieved.

Zinc can be tested along with other trace elements (e.g iron, copper & selenium) to identify deficiencies where a person may benefit from supplementation.
When is it requested?

When a person displays clinical symptoms that may be associated with zinc deficiency, or where there is a risk of developing deficiency, the measurement of zinc can determine if supplementation is required. Where supplementation is necessary the measurement of zinc can be used to assess when adequate concentrations are achieved.
What does the test result mean?

Zinc decreases in response to infections so a low result may not necessarily mean a person is zinc deficient. Results should be interpreted with clinical symptoms and clinical history.

Since zinc is transported mainly bound to albumin it can be useful to interpret zinc results alongside albumin concentration. For example a low zinc concentration with a normal albumin can suggest zinc deficiency, whereas a low zinc with a low albumin concentration can suggest an acute phase response to infection and not necessarily zinc deficiency.

High results are rarely seen as excess zinc can be excreted in the urine/faeces. Excessive supplementation of zinc can be toxic to the kidneys, and can cause other nutrient deficiencies, such as for copper. Symptoms of zinc toxicity include nausea, vomiting, lethargy and drowsiness.
Is there anything else I should know?

Medications such as steroids & oral contraceptives can reduce circulating concentrations of zinc. Pregnancy is associated with lower zinc concentrations due to increased circulating hormones in the body.

Medications such as antibiotics and iron may compete with zinc for intestinal absorption.
Should everyone’s zinc concentrations be measured to check for deficiency?

General screening for zinc deficiency is not recommended. If a person displays clinical symptoms that might be related to zinc deficiency then the measurement of zinc may be useful to assess whether supplementation is recommended.
When is it recommended to measure urine zinc concentrations?

The measurement of urine zinc may be useful for patients on total parenteral nutrition (nutrition that is delivered directly into the blood/bypassing the oral route) who fail to respond to supplementation, in order to assess any excessive losses in the urine.
Should I be taking zinc supplements?

Most individuals have an adequate supply of zinc in their diet and supplementation is not necessary. However, if you have any concerns please consult your GP who can investigate any symptoms and advise if testing is required.

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