Lactose intolerance genetic blood test in Chiswick

What the test measures

Lactase is the enzyme in the small intestine that breaks down lactose, the natural sugar in milk. Every baby makes it, but in many adults production falls after childhood, a pattern known as lactase non-persistence. Whether you keep making lactase depends largely on a variant close to the LCT gene, and this test checks that variant.

Lactase non-persistence is the most common pattern worldwide and is especially frequent in people with East Asian, African, South Asian or Middle Eastern heritage. When lactase is low, undigested lactose is fermented in the bowel, which can cause bloating, wind, cramps and loose stools after dairy. Not everyone with the genetic pattern has symptoms, and many tolerate small amounts.

The price includes the blood sample at our Chiswick clinic, analysis at the Randox accredited laboratory, a practitioner review of your result and a GP feedback report on request.

Who it is for

• You often feel bloated or uncomfortable after milk, ice cream or soft cheese.
• You want to know whether cutting out dairy is likely to help before changing your diet.
• You have already reduced dairy and would like a test that does not require drinking lactose.
• Lactose intolerance runs in your family.
• Your practitioner is working through possible causes of digestive symptoms with you.

Understanding your result

Your report shows whether your genetic pattern is linked to lactase persistence or non-persistence. A non-persistence result means you are likely to make less lactase as an adult, which supports, but does not prove, lactose intolerance as the cause of symptoms. A persistence result makes primary lactose intolerance unlikely, though it does not rule out lactose problems from other causes, such as a recent gut infection or coeliac disease, which can temporarily damage the gut lining.

Genetic results describe a tendency rather than how your gut is working today, and a negative result does not remove all risk of symptoms. Your practitioner will read it alongside your history, and complex questions can be referred to a specialist. The result is a prompt for discussion, not a diagnosis.

Preparing for your test

No fasting is needed, and unlike breath tests you do not need to drink lactose or change your diet beforehand. Your genes are not affected by food or medicines, so you can test at any time of day.

If your symptoms might have another cause, our coeliac blood tests and calprotectin stool test look at different parts of the picture. You can also see every blood test and price in Chiswick.

Questions

How much is a lactose intolerance genetic test in Chiswick?

The Lactose Intolerance Genetic Test costs £149 at our Chiswick clinic. The price covers the blood sample, accredited laboratory analysis, a review with a practitioner and a GP feedback report on request.

Is lactose intolerance the same as a milk allergy?

No. A milk allergy is an immune reaction to milk proteins and can be serious. Lactose intolerance is a difficulty digesting milk sugar and causes digestive symptoms rather than an allergic reaction.

Do I need to eat dairy before the test?

No. This test reads your genes, so your diet makes no difference to the result.

If the result shows non-persistence, must I avoid all dairy?

Not necessarily. Many people manage small amounts, hard cheeses or lactose-free products. If you cut back, it is worth checking your calcium intake with your practitioner or a dietitian.