Zinc Deficiency, Excess and Supplementation - Diagnosis

Authored by Dr Mary Harding, 30 May 2017

Patient is a certified member of
The Information Standard

Reviewed by:
Dr John Cox, 30 May 2017

The first test is a blood test to check levels of zinc. However, the levels in blood do not necessarily tally with the levels of zinc within the cells of the body. So it is possible to have a normal blood zinc level but actually be deficient in zinc. If the symptoms match and there is a likely cause of zinc deficiency then in some cases this may be assumed, regardless of the blood result.

If you have an excess of zinc, however, this should be clear from the blood test result.

It may be possible to analyse zinc levels in cells by checking levels of zinc in hair in future. However, this is not yet widely available.

You may also have blood tests for related elements such as:

  • Iron
  • Copper
  • Calcium
  • Vitamin D
  • Vitamin B12
  • Magnesium

This is because a deficiency or excess of zinc can affect absorption of some of these other elements, and vice versa. Also where there is a problem absorbing vital nutrients, others may also be deficient. So multiple deficiencies may need checking out.

Sometimes other tests are needed to exclude other causes for the symptoms, such as blood tests for thyroid function.

If you are severely unwell from either zinc deficiency or excess, other tests may be needed. For example, blood tests to check your kidney function, or tests to make sure you are not lacking in fluid (dehydrated).

Where babies have developed zinc deficiency early in life, or where there is a family history, genetic testing for the rare condition acrodermatitis enteropathica may be relevant.

Further reading and references

  • Evans JR, Lawrenson JG; Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration. Cochrane Database Syst Rev. 2012 Nov 1411:CD000254. doi: 10.1002/14651858.CD000254.pub3.

  • Singh M, Das RR; Zinc for the common cold. Cochrane Database Syst Rev. 2013 Jun 186:CD001364. doi: 10.1002/14651858.CD001364.pub4.

  • Lazzerini M, Wanzira H; Oral zinc for treating diarrhoea in children. Cochrane Database Syst Rev. 2016 Dec 2012:CD005436. doi: 10.1002/14651858.CD005436.pub5.

  • Allan GM, Arroll B; Prevention and treatment of the common cold: making sense of the evidence. CMAJ. 2014 Feb 18186(3):190-9. doi: 10.1503/cmaj.121442. Epub 2014 Jan 27.

  • Saper RB, Rash R; Zinc: an essential micronutrient. Am Fam Physician. 2009 May 179(9):768-72.

  • Zinc. Consumer Fact Sheet; National Institute of Health Office of dietary supplements

  • Acrodermatitis enteropathica; DermNet NZ

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