Lactose intolerance test

Lactose intolerance test

Suspecting a lactose intolerance? If you experience some of the symptoms of lactose intolerance, it might be a good idea to get a test to see if you’re actually intolerant. In this article we’ll go through three different lactose intolerance tests – but remember to always consult or doctor if you suspect that you’re lactose intolerant or you experience discomforts. Get to know the different test options here.

Testing for lactose intolerance

Before conduction a lactose intolerance test, your doctor will probably ask questions about your symptoms, when they occur, how often, what foods and drinks you assume trigger the symptoms, etc. so it’s a good idea to be prepared for these questions. Maybe take a few weeks where you write down what you eat, which symptoms you experience and when. That way your doctor has a good base to start from.

A simple lactose intolerance test can easily clarify any questions regarding lactose intolerance. Here’s an overview of the three different test options:

  • Hydrogen breath test
  • Lactose tolerance test (LTT)
  • Elimination challenge test

Ask your doctor or dietician about the options and what works best for you.

Hydrogen breath test

A hydrogen breath test is a simple test that can be used to determine if you may be lactose intolerant. In this test, hydrogen (H2) is measured in the exhaled air before and after drinking a sugar solution with lactose.

To take the test, you’ll make a breath sample by blowing into a bag. The breath sample is then tested to check the amount of hydrogen. This is measured in ppm (parts per million). Afterwards, you’ll have to drink a sugar solution to add lactose to your system. In the following hours, your breath will be tested every 15 minutes to measure the development of the hydrogen level.

So, to sum up; a hydrogen breath test for lactose intolerance happens as follows:

  • You breathe into a bag
  • Your breath sample is tested to measure the hydrogen level
  • You drink a lactose solution (a sugar solution)
  • Your breath is tested every 15 minutes for a few hours.

Hydrogen gas is produced by gut bacteria during the breakdown of sugars such as lactose. By determining the amount of hydrogen gas in exhaled air at different times, it can be determined whether there is a lactose intolerance. If the hydrogen level is more than 20ppm above the level of the sample you gave before drinking the lactose solution, it’s likely that you’re lactose intolerant, because an intolerance can cause the bacteria in the large intestine to produce more hydrogen than normal.

Lactose tolerance test (LTT)

A lactose tolerance test is a blood test. You’ll drink a lactose solution and then the doctor will take a blood sample to test how much blood sugar (glucose) it contains. Then blood is taken at various times to determine the blood sugar level.

In short, a lactose tolerance test happens as follows:

  • You drink a lactose solution
  • Blood samples are taken regularly for a period of time to measure the blood sugar level.

If the blood sugar level doesn’t rise or only rise slowly, there may be a lactose intolerance, as your body shows to be unable to break down the lactose into glucose. You can read more about the digestion of lactose in our article What is lactose?

Elimination-provocation test

In an elimination-provocation test, a lactose-free diet is first used (so lactose is literally eliminated). If the symptoms decrease or are completely gone, there is a high chance of a lactose intolerance. After a while, lactose is added to the diet again, whereby complaints are ‘provoked’. If the symptoms return, you can be diagnosed with ‘lactose intolerance’.

The elimination-provocation test in steps:

  • Elimination – lactose is removed completely from your diet. If the symptoms reduce or disappear, you might be intolerant.
  • Provocation – lactose is added to your diet. If the symptoms come back, you might be intolerant.

The elimination-provocation test for lactose intolerance is quite easy in the sense that you don’t need any professional help to carry out the test as it’s the case with the breath test and the blood test. However, you shouldn’t start the elimination-provocation test before talking to your doctor.

Check out our delicious lactose-free recipes for yummy meals and snacks without lactose.

Lactose intolerance test at home

It’s not advisable to try making a lactose intolerance test at home if you haven’t consulted your doctor first. You may be advised to try the elimination-provocation test, but you shouldn’t start experimenting without your doctor’s accept as symptoms of lactose intolerance can be similar to symptoms of other things such as milk allergy, which might cause severe reactions if you start doing your own lactose intolerance test at home.

Fortunately, you can replace the dairy products with lactose-free milk products from Arla. And with our lactose-free recipes you can also get a dose of inspiration for delicious dishes! 

A lactose-free diet is not the only solution for dealing with lactose intolerance. For example, you can take lactase tablets or pills, so that you can still digest lactose. For more information, it is best to consult your doctor or nutritionist.

The test result isn’t everything

Some people experience a digestive discomfort without being lactose intolerant. That’s perfectly normal, and if you feel bloated or otherwise unwell after consuming products with lactose, it may help you to choose lactose-free alternatives anyway. Lactose-free products are not just for people with lactose intolerance, and if it makes you feel better why not do it? Allow yourself to live with all your might, and don’t let a bloated stomach limit you. Pour it, slurp it, splash it – Arla LactoFREE is here to help you feel at ease no matter what the result of your lactose intolerance test says!


Confused? Fear not – we got you covered! Here below we’ve listed some frequently asked questions about testing for lactose intolerance. Remember to always consult your doctor if you’re experiencing any symptoms or you have any questions about lactose intolerance.​

Is there a lactose intolerance test?

Yes, some of the most used lactose intolerance tests are elimination-provocation test, hydrogen breath test, and lactose tolerance blood test.

What is a lactose intolerance test?

With a lactose intolerance test you can test if you’ve enough lactase in your body to digest lactose. In other words: whether you’re lactose intolerant or not.​

What test determine lactose intolerance?

There are several tests for lactose intolerance. Your doctor can advise you to the best one for your situation.

How do doctors check for lactose intolerance?

Your doctor can make different lactose intolerance tests. The lactose tolerance test is a blood test, whereas the hydrogen test is a breath test. Both a carried out by the doctor and takes a few hours. The elimination-provocation test takes longer, as you first need to remove lactose from your diet and afterwards reintroduce it to see if there are any changes in your symptoms.

How to get a lactose intolerance test?

If you suspect that you’re lactose intolerant, contact your doctor. He or she can give you advice about what test is the best for you.

What is a breath test for lactose intolerance?

A hydrogen breath test measures the hydrogen level in the air when you exhale. By testing the air before and after you drink a sugar solution, it’s possible to see the development in the hydrogen level. If the hydrogen level rises significantly, there is a strong probability of you being lactose intolerant.

What is a lactose tolerance test?

The lactose tolerance test is a blood test. The doctor watches the blood sugar over a few hours to determine whether lactose intolerance is an option or not.

How do you know if you’re lactose intolerant?

If you experience symptoms such as bloating or diarrhoea after eating or drinking dairy products, it may be a sign of lactose intolerance. If you suspect that you’re lactose intolerant, you should always consult your doctor. He or she can advise you on how to find out if you’re lactose intolerant – and provide you with a lactose intolerance test if needed.