Food Allergy & Intolerance Tests

Lactose, a disaccharide, is not normally absorbed directly from the gut, but is broken down into glucose and galactose by the enzyme lactase. If the lactase is absent (or insufficient for the dietary load of lactose), then non-absorbed lactose will be the pass into the lower small intestine and the colon. This may result in diarrhoea with cramps and flatulence, the symptoms of the condition known as “lactose intolerance”, which is not an allergic condition but a digestive problem.

In such cases, the lactose, on reaching the large bowel is fermented by colonic bacteria producing hydrogen and sometimes methane.  These gasses pass across the gut wall into circulation and are exhaled in the breath.

This test requires the collection of breath samples after avoiding dietary fibre, resistant starch, complex carbohydrates and dairy products for 24 hours, followed by an overnight fast.  An initial breath sample is collected, the patient then consumes 25G of lactose (supplied with the test kit) and then further breath samples hourly for three hours.  A negative test will return very low levels of hydrogen and methane throughout, whereas a patient with lactose intolerance will exhibit raised levels of breath gasses when the lactose reaches the colon, as illustrated in the sample report which can be viewed below.

Test datasheet: Lactose Intolerance datasheet

Sample report:  Lactose Intolerance Breath Test sample report

Patient instruction sheet:  Lactose Intolerance Breath Test patient instructions.