Tobias is a 19 year old retail assistant who presents to the GP requesting a test for Coeliac disease. Over the last year he has noticed he is feeling fatigued and suffered from abdominal bloating and intermittent diarrhoea. He says he suffers from Irritable Bowel Syndrome and has found that cutting wheat from his diet significantly helps symptoms. You notice he has never had a test for Coeliac disease and agree to investigate further along with other blood tests.
Which one of the following options regarding testing for Coeliac disease is least correct?