Coeliac disease can only be definitevely diagnosed by a small bowel biopsy, says doctors warning against in-pharmacy tests

In-pharmacy tests for coeliac disease are unreliable, say doctors.

"Coeliac disease is a notoriously difficult to diagnose illness and can only be definitively diagnosed by a small bowel biopsy performed by a doctor," says AMA (NSW) president Saxon Smith.

In-pharmacy tests are unreliable and can have false positive and false negative results, Dr Smith said in a statement.

The disease also has a range of symptoms similar to other serious conditions.

"Even a true negative test for coeliac disease from in-pharmacy testing may give someone with a different serious illness, false confidence," he said.

In people with the disease, the immune system reacts abnormally to gluten, causing small bowel damage.

On its website, Coeliac Australia says a definitive medical diagnosis is essential as it's a serious condition with lifelong implications.