Some patients wait 11 years for diagnosis of gluten intolerance
Some 23 per cent consulted their doctor about their symptoms for 11 years, while a further 11 per cent asked their doctor for help for over 20 years. The average length of diagnosis was 13 years.
Coeliac disease can lead to diarrhoea, bloating and abdominal pain and is caused by the body's immune system mistaking gluten for a foreign organism.
Gluten is a protein found in a number of grains including wheat, barley and rye, and the only treatment is for sufferers to avoid pasta, cakes, breakfast cereals and most type of bread.
If left untreated, coeliac disease - which affects about one in every 100 people in the UK - can cause osteoporosis, growth defects and infertility.
Women are two to three times more likely to develop the illness than men.
The poll of more than 1,600 people with the condition found almost 60 per cent were also diagnosed with anaemia even without a test. Other conditions diagnosed by doctors included anxiety and depression, gastroenteritis, gallstones, ulcers, ME or chronic fatigue syndrome and appendicitis. Some people were told they were a hypochondriac.
Almost a third thought GP knowledge about the disease was poor or very poor, and almost six in 10 were misdiagnosed with irritable bowel syndrome.
Liberal Democrat MSP Jim Tolson, convener of the cross party group on coeliac disease said more support was needed in Scotland for those with the disease.
He said: "Coeliacs don't always get the help and support they need. It is crucial that health professionals are more aware of the symptoms of celiac disease, which can now be tested by a straightforward blood test.
"The availability of prescription foods is restricted. I urge the Scottish Government to give more help to those suffering from coeliac disease by making more expensive specialist foods available on prescription."
Not everyone with coeliac disease experiences gut-related symptoms, and it can show through mouth ulcers, skin problems, depression, nerve problems and even recurrent miscarriages.
Sarah Sleet, chief executive of Coeliac UK, which carried out the poll, said guidelines for GPs should be driving up diagnosis rates.
She said: "It is too early to tell if the guidelines are improving diagnosis rates but as a charity we are receiving around 1,000 new member requests a month from people who have just been diagnosed."But with around 500,000 people currently undiagnosed in the UK there is still a long way to go and it will be another 30 years at the current rate of progress before we crack the problem."
She added that a GPs needed to be fully aware of the disease to "prevent years of misery for patients and needless waste of hard-pressed NHS resources".
Sleet said there needed to be a change in GPs' attitudes, possibly by offering financial incentives so they become better at spotting the disease.
Guidelines to GPs suggest relatives should also be tested as coeliac disease runs in families, yet 79 per cent of people polled said this had not happened.
In questions to health secretary Shona Robison in the Scottish Parliament last month, she said GPs were supported by guidelines on the management of coeliac disease.