Other diagnostic tests for food intolerance

No available investigation can accurately identify all the foods causing a patient’s symptoms. Breath tests and duodenal biopsies for lactose and fructose malabsorption are not specific or sensitive. Many unorthodox and unproven diagnostic tests are available, but these should not be used as evidence is lacking.

Skin-prick testing and serum-specific immunoglobulin E (IgE) testing should not be used to investigate food intolerance unless food allergy is suggested by the clinical history. False-positive results are common and may lead to potential harm from inappropriate dietary restrictions, with nutritional implications for the patient (particularly children) and unnecessary fear and anxiety (particularly for the family or carers).