A genetic test is now available to assist in the diagnosis of lactose intolerance in both children and adults.

Key points

• Lactose intolerance affects approximately 75% of the population.
• Genetic testing can confirm lactose tolerance (also referred to as lactase persistence).
• The test differentiates between primary lactose intolerance, due to lactase deficiency, and secondary causes of lactose intolerance, due to other more serious conditions that affect the small bowel.
• The test is not affected by intercurrent illness and can be performed non-invasively on patients of all ages.

The test only needs to be performed once during a person’s lifetime.

How does the test work?