Hi Tina. Yes I am in the UK. I had my test done at Biolab which is a laboratory specialising in nutritional and environmental medicine. However they can only perform tests requested by a medically qualified doctor. I paid and saw a doctor privately who took the blood, sent if off and gave me the results. I know my levels have increased as I keep paying Biolab to have the test redone. If you would like a recommendation for a doctor I can let you know who I saw but have a look at the Biolab web site first because they do all kinds of tests besides the magnesium. http://www.biolab.co.uk (You could also ask your own GP if he is willing to do the test - most are not but mine will help out now)