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Lactose intolerance genetic testing

Key points

  • 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?

Testing is now available to detect the genetic variant (LCT-13910C>T) that accounts for close to 100% of lactase persistence in Europeans. Three other genetic variants that have a similar effect and are more common in non-European populations are also detectable. These variants are thought to act as enhancers of the lactase gene that in turn stimulates lactase production. The clinical utility of this test is its application in excluding primary lactose intolerance as the underlying cause of gastrointestinal symptoms, by detecting a genetic variant that results in lactase persistence. It may also assist in distinguishing between primary lactose intolerance and lactose intolerance secondary to other conditions that affect the small bowel, such as gastroenteritis, inflammatory bowel disease and coeliac disease.

Arranging a test

1 > Complete a standard pathology request form to refer your patient for ‘lactase persistence’ or ‘lactose intolerance genetic testing’. 

2 > Send your patient to any Sonic Healthcare pathology collection centre for a blood test or buccal swab. No special preparation or booking is necessary.

3 > The sample is tested at one of our NATA-accredited laboratories supervised by a genetic pathologist.

4 > The result is reported back to you, usually within 5 business days of the laboratory receiving the patient’s sample.


Medicare does not cover the cost of the lactose intolerance test and your patient will receive an invoice. Please refer to test details for current pricing.

For training videos on this subject and other genetic tests, please visit our Doctor Education website.