Zinc is a trace element used by many enzymes involved in cell growth, wound healing, immune function and the processing of protein, fat and carbohydrate. This test measures the zinc in your serum. Zinc is one of the more delicate tests to collect accurately: food, the time of day, recent infection and contamination during sampling can all shift the result, so preparation matters.
What is measured
- Serum zinc (measured): zinc circulating in the blood, mostly carried on albumin.
Useful for
- Checking for low zinc when you have symptoms such as poor wound healing, hair loss or a dermatitis-type rash, or a condition affecting absorption
- Reviewing your level if you take zinc supplements regularly
- Following up a previous abnormal zinc result under the same conditions
The price covers laboratory analysis and the laboratory's report with its reference range. Interpretation and consultations are optional.
Sample: venous blood sample, ideally fasting and in the morning. Biomarkers: 1.
Zinc Blood Test
- Serum zinc (measured): usually reported in µmol/L.
Laboratories normally collect zinc into a dedicated trace-element tube. Standard tubes, stoppers and gels can contain small amounts of zinc, and because red blood cells contain around ten times more zinc than serum, any damage to the cells (haemolysis) can raise the result. Careful collection and prompt handling help keep the result accurate.
Albumin, C-reactive protein (CRP) and copper are not included. Albumin and an inflammation marker can help explain a low zinc result, and a clinician may request them if your result is low.
The body has no dedicated zinc store, so a steady intake from food matters. The NHS lists meat, shellfish, dairy foods such as cheese, bread and cereal products such as wheatgerm as good sources. Zinc is needed to make new cells and enzymes, to process the main nutrients in food, and to heal wounds.
Only a small fraction of the body's zinc circulates in the blood. Lab Tests Online UK notes that about 80% of it is carried on albumin and about 20% on another protein, alpha-2-macroglobulin. When the body responds to infection, injury or inflammation, zinc is redistributed out of the bloodstream, so serum zinc falls even if total body zinc has not changed.
Zinc is also closely involved in the immune system. A 2017 review by Wessels, Maywald and Rink describes how zinc acts as a signal inside immune cells and how deficiency impairs several immune functions. The same review makes an important point for anyone considering this test: there is still no fully reliable biomarker of zinc status, and serum zinc is the best widely available option rather than a perfect one.
Your report will show the laboratory's reference range. When reading it, keep in mind the factors that can lower or raise zinc without reflecting a true change in your zinc status:
- Infection or inflammation: zinc falls during an acute illness and recovers afterwards. Lab Tests Online UK notes that low zinc with low albumin may reflect this kind of response, whereas low zinc with normal albumin is more suggestive of deficiency.
- Meals and timing: zinc can drop after eating, so a non-fasting or afternoon sample may read lower than a fasting morning sample.
- Medicines and physiology: steroids, oral contraceptives and pregnancy can lower levels.
- Contamination and haemolysis: both can raise the result falsely.
Recognised causes of genuinely low zinc include heavy alcohol use, conditions affecting absorption, severe burns and, rarely, inherited disorders. A single low result is a prompt to repeat the test under the right conditions or discuss it with your GP. It is not proof of deficiency.
A high result is rare from food. It usually reflects supplements or contamination. Long-term high-dose zinc reduces how much copper the body absorbs, which can lead to anaemia and weakened bones, according to the NHS. Where a result needs medical attention, we will advise you to see your GP and, with your consent, can write to them.
Lab Tests Online UK advises that zinc testing is not recommended as a general screening test. It is most useful when there is a reason to suspect a problem, such as:
- symptoms associated with low zinc, such as poor wound healing, hair loss or a dermatitis-type rash, which also have many other causes;
- conditions that reduce absorption from the gut, or heavy alcohol use;
- taking zinc supplements for a long time, particularly above the NHS guidance of no more than 25mg a day unless advised by a doctor.
May find it useful: people with risk factors or symptoms that could relate to zinc; people taking zinc supplements who want to check they are not overshooting; people following up a previous result.
May not need it: healthy people with a varied diet and no symptoms. Lab Tests Online UK does not recommend general screening.
Better to wait or seek care elsewhere: if you are currently unwell with an infection, the result is likely to be low for reasons unrelated to diet, so book once you have recovered. Non-healing wounds, unexplained hair loss or persistent rashes should be assessed by your GP, who can look for other causes.
Established: zinc is essential for normal immune function, wound healing and cell renewal throughout life.
Associations: the 2017 Wessels review reports that low zinc status is common in older people and discusses its possible role in immune ageing, including weaker vaccine responses and more low-grade inflammation in later life. These observations do not establish that low zinc causes immune ageing.
Emerging research: in studies the review cites, zinc supplementation improved some laboratory measures of immune function in older adults. Changes in laboratory markers are not the same as fewer infections or longer life, and those outcomes have not been shown.
Not supported: taking extra zinc when your level is already adequate as an anti-ageing measure. High doses carry a real risk of copper deficiency.
- Book a morning appointment and come fasting (water is fine), as zinc can fall after eating.
- Wait until you have fully recovered from any infection or feverish illness.
- If you take a zinc supplement, take your usual dose after the sample rather than before, and tell us the dose.
- Tell us if you take steroids or an oral contraceptive, or if you are pregnant.
- If you are repeating the test, use the same timing and fasting conditions as before.
Choose how your sample is taken when you book. We confirm the collection option, any collection fee and the expected turnaround time before you book.
- Juvenology Clinic, Maidstone (82 King Street, Maidstone ME14 1BH): Available.
- Partner collection location, including London: Available on request. We confirm availability for your postcode before you book.
- Postal home finger-prick kit: Ask before ordering. We offer a home kit only where the laboratory confirms this test is suitable for a finger-prick sample.
Sample: Venous blood sample (serum, trace-element tube as specified by the laboratory)
Collection notes: Fasting morning sample recommended, taken when you are well. Zinc needs a trace-element collection tube and careful handling to avoid contamination and haemolysis, so a venous sample is preferred; a postal finger-prick kit is offered only if the laboratory confirms it is suitable.
The price of this test covers laboratory analysis and the laboratory's results report. The report lists each result beside the laboratory's reference range.
Beyond the blood test: optional support, priced separately
- Personalised written interpretation report: £50
- General consultation: £50
- Results consultation (results discussion and follow-up advice): £100
- Personalised programme: from £150, after we assess whether a programme suits you
Consultations are with Marina, an NMC-registered nurse with an Executive MSc in Longevity from the Geneva College of Longevity Science. She explains what your results show and how they relate to lifestyle. No prescription service is offered with these tests.
If a result suggests you need medical follow-up, we will recommend that you see your GP and, with your consent, can provide a letter to take with you. A blood test cannot rule out every condition. If you have symptoms, speak to your GP or NHS 111, and call 999 in an emergency.
Why do fasting and timing matter so much?
Serum zinc falls after meals and varies through the day. A fasting morning sample gives a more consistent result and makes repeat tests comparable.
I had a cold last week. Should I wait?
Yes. Infection and inflammation lower serum zinc temporarily. Waiting until you are well avoids a misleading low result.
Can I do this test with a home finger-prick kit?
Zinc is sensitive to contamination from skin and to haemolysis, both more likely with finger-prick samples. A venous sample at the clinic is preferred, and a home kit is only offered if the laboratory confirms it is suitable.
I take zinc supplements. Should I check my copper too?
Long-term high-dose zinc can reduce copper absorption. If you have taken more than 25mg a day for a long time, discuss copper testing with your GP or consider our copper blood test.
Will a normal result prove my zinc intake is adequate?
It makes significant deficiency less likely, but serum zinc is an imperfect marker of body zinc, so the result should be read alongside your diet and symptoms.
Is interpretation included?
The price covers analysis and the laboratory's report. A personalised written interpretation report (£50) or a results consultation (£100) can be added.
- Zinc. Lab Tests Online UK. https://labtestsonline.org.uk/tests/zinc
- Wessels I, Maywald M, Rink L. Zinc as a gatekeeper of immune function. Nutrients, 2017;9(12):1286. https://doi.org/10.3390/nu9121286
- Vitamins and minerals: others (zinc). NHS. https://www.nhs.uk/conditions/vitamins-and-minerals/others/
