Genetic Lactose Intolerance
Private Genetic Lactose Intolerance test in London for £160, analysing two lifelong genetic markers with results expected in around 4–6 weeks.
Turnaround time
4-6 weeks
Biomarkers count
2
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Overview of the Genetic Lactose Intolerance
The Genetic Lactose Intolerance test analyses two inherited genetic variants associated with whether lactase enzyme production is likely to persist or decline during adulthood.
The test contains 2 genetic biomarkers: C13910T and G22018A.
Lactose is the principal naturally occurring sugar in milk.
To absorb lactose efficiently, the small intestine produces an enzyme called lactase, which splits lactose into smaller sugars that can be absorbed.
In many people, lactase production naturally decreases after childhood.
When insufficient lactase is available, some lactose passes undigested into the colon, where intestinal bacteria ferment it.
This process can produce bloating, abdominal discomfort, excessive gas and diarrhoea after consuming lactose-containing foods.
The C13910T and G22018A variants are located within a regulatory region associated with the MCM6/LCT pathway controlling lactase persistence.
Certain inherited combinations are associated with continued lactase production into adulthood, while others are associated with genetically determined lactase non-persistence.
Importantly, this test primarily assesses primary inherited adult lactose intolerance.
It does not diagnose secondary lactose intolerance caused by temporary or persistent damage to the intestinal lining from gastroenteritis, untreated coeliac disease, inflammatory bowel disease or another gastrointestinal condition.
A person can therefore have a genetic pattern associated with lactase persistence but still develop temporary lactose intolerance because of intestinal illness.
Lactose intolerance is also different from cow's milk protein allergy, which involves an immune response to milk proteins rather than difficulty digesting lactose.
What Does the Genetic Lactose Intolerance Test Check?
The test analyses two genetic variants associated with regulation of the lactase enzyme, providing information about inherited lactase persistence or non-persistence. This test measures 2 genetic biomarkers.
C13910T
Analyses a regulatory genetic variant associated with persistence or reduction of lactase production into adulthood.
G22018A
Analyses an additional genetic variant associated with inherited patterns of lactase persistence and adult lactose digestion.
Who May Benefit From the Genetic Lactose Intolerance Test?
Genetic testing may be useful when recurrent symptoms after dairy suggest lactose intolerance and the aim is to determine whether there is an inherited tendency towards reduced adult lactase production.
People with repeated bloating after milk or lactose-containing foods - Genetic testing can determine whether primary lactase non-persistence is plausible.
People with diarrhoea after dairy consumption - Lactose malabsorption is one possible explanation.
People with abdominal cramping after consuming milk - Colonic fermentation of undigested lactose can produce discomfort.
People with excessive gas following lactose-containing foods - Bacterial fermentation produces gases within the colon.
People uncertain whether lifelong dairy symptoms have a genetic basis - The result can provide information about inherited lactase persistence.
People who want a one-time genetic assessment - DNA does not change according to diet or age.
People distinguishing lactose intolerance from other food-related problems - The genetic result can help clarify one specific biological mechanism.
People already following a lactose-free diet - Genetic testing remains possible because lactose consumption is not required.
How to Prepare
Because this is a DNA-based investigation, food intake and current lactose avoidance do not alter the genetic result.
There is no need to deliberately provoke gastrointestinal symptoms by consuming lactose before genetic testing.
The inherited variants remain the same regardless of recent diet.
Symptoms and Reasons to Consider the Genetic Lactose Intolerance Test
Symptoms of lactose intolerance usually occur after consuming enough lactose to exceed the individual's digestive capacity, and the amount tolerated can vary considerably.
Bloating after milk or dairy products - Undigested lactose can be fermented by intestinal bacteria and increase gas production.
Excessive flatulence - Fermentation of lactose can generate hydrogen and other gases.
Abdominal cramps after dairy - Gas and increased intestinal fluid can cause discomfort or cramping.
Loose stools or diarrhoea - Unabsorbed lactose can draw water into the intestine.
Symptoms that depend on the quantity of dairy consumed - Many people with reduced lactase activity can tolerate smaller amounts of lactose.
Symptoms improving with lactose-free foods - Improvement can support suspicion of lactose malabsorption but is not diagnostic by itself.
A family history of adult lactose intolerance - Lactase persistence patterns are strongly influenced by genetics.
Blood in the stool, unexplained weight loss, persistent severe diarrhoea, anaemia or significant abdominal pain should not simply be attributed to lactose intolerance.
These features require appropriate gastrointestinal assessment for other possible causes.
How to Book Your Genetic Lactose Intolerance Test
The Genetic Lactose Intolerance test can be booked privately without the need for a lactose challenge or special dietary preparation.
Choose the Genetic Lactose Intolerance
Select the two-marker genetic test online.
Select your sample collection option
Choose the appropriate in-clinic or professional collection pathway.
Attend your appointment
The required specimen is collected for genetic analysis.
Laboratory analysis
C13910T and G22018A are analysed to assess the inherited lactase-persistence pattern.
Receive your results securely
Your authorised genetic report is delivered securely for interpretation.
When Will I Receive My Results?
The current expected turnaround for the Genetic Lactose Intolerance test is approximately 4–6 weeks after your specimen reaches the laboratory.
Genetic analysis requires DNA processing, genotype determination, quality-control review and laboratory authorisation.
This takes longer than routine biochemistry or allergy blood testing.
Turnaround begins from laboratory receipt rather than necessarily from the day of sample collection.
Once a valid genetic result has been established, the test normally does not need to be repeated because the inherited variants do not change during life.
Understanding Your Results
The report identifies the genetic variants present at C13910T and G22018A and interprets whether the pattern is associated with lactase persistence or lactase non-persistence.
A genetic pattern associated with lactase non-persistence supports an inherited tendency towards reduced adult lactose digestion.
It does not predict exactly how much lactose will trigger symptoms.
Individual tolerance varies, and many people with reduced lactase activity can tolerate small portions of lactose without significant symptoms.
A genetic pattern associated with lactase persistence makes primary genetically determined adult lactose intolerance less likely.
However, it does not exclude secondary lactose intolerance caused by intestinal mucosal damage.
The test also does not diagnose cow's milk protein allergy, coeliac disease, IBS or other causes of bloating and diarrhoea.
Why Book With London Blood Tests?
This genetic test provides a one-time assessment of inherited lactase persistence without requiring the patient to consume lactose or deliberately provoke symptoms.
Two genetic variants analysed - C13910T and G22018A are assessed.
Lifetime genetic result - The inherited pattern does not change over time.
No lactose challenge required - You do not need to consume dairy before testing.
Suitable while lactose-free - Dietary avoidance does not alter DNA.
Helps distinguish inherited susceptibility - The test specifically addresses primary genetic lactase non-persistence.
Useful alongside gastrointestinal assessment - Results can help distinguish inherited lactose intolerance from secondary causes.
Private testing in London - Professional sample collection can be arranged.
Secure reporting - Receive your authorised genetic report confidentially.
Clear pricing - The Genetic Lactose Intolerance test costs £160.
Private Genetic Lactose Intolerance Test in London
London Blood Tests provides private Genetic Lactose Intolerance testing for people seeking information about inherited adult lactase persistence.
The test costs £160 and analyses 2 genetic biomarkers: C13910T and G22018A.
Results are expected approximately 4–6 weeks after laboratory receipt.
The result can identify inherited susceptibility to primary lactose intolerance but does not exclude secondary lactose malabsorption or other gastrointestinal conditions.