Three Types of Lactose Intolerance Test

Lactose Intolerance

Lactose intolerance is widely prevalent in the world today. Almost every other person seems to have this ailment.

However, while the root cause remains a matter of heated discussion amongst researchers, knowing the symptoms and when to get a lactose intolerance test is the best approach to be a step ahead.

Lactose Intolerance: At a Glance

This digestive disorder results from the body’s incapability to produce adequate levels of lactase, the chemical enzyme. Lactase digests lactose into smaller, simpler sugars, making them easier to digest and absorb.

Lactase predominantly exists in the small intestine. When levels aren’t enough, bacteria get a chance to ferment the lactose. One of the end products of this process is hydrogen. 

When to Get a Lactose Test?

A lactose test is the best way to diagnose this condition accurately. Your gastroenterologist will suggest getting a lactose test if you come in with any of the following complaints after lactose consumption:

  • Diarrhoea and constipation
  • Gassy stomach
  • Abdominal discomfort and cramping

Types of Lactose Tests:

Hydrogen Test

This test measures and monitors the quantity of hydrogen in your breath right after lactose consumption. Because this method is so simple and easy to carry out, it’s frequently used to diagnose this ailment. 

The procedure is as follows:

  1. You’ll be requested to blow up a balloon to check your initial hydrogen levels
  2. Your doctor will provide you with a lactose-containing slurry which you’re expected to drink
  3. Your doctor will instruct you to breathe into the balloon again
  4. The hydrogen gas levels will be monitored in equal intervals and compared with the baseline value

As mentioned earlier, lactose intolerance leads to increased hydrogen gas amounts. Therefore, if the levels are reported to be abnormally high, this is a clear indication of lactose intolerance.

Blood Sugar Test

Blood Sugar Test

The blood sugar test, also referred to as the lactose tolerance test checks the amount of glucose in your blood subsequent to lactose intake.

First, a small blood sample will be extracted using a syringe and needle from your vein. This step is vital to establish a base value later used for comparison.

Next, your medical professional will hand you a lactose-containing drink of known lactose concentration. Once you’ve finished the drink, blood samples are taken periodically to track glucose concentrations.

Digested lactose produces glucose in the bloodstream. Therefore, if your glucose levels remain persistently low even after the drink, there’s a possible chance you have lactose intolerance.

Stool Test

This test is mostly only used for toddlers and infants. First, the pH levels of the stool are measured. Low pH values indicate acidity due to lactic acid formed from fermentation in the small intestine. Hence, the acidic stool is a giveaway sign of lactose intolerance.


Lactose intolerance can be challenging to diagnose since its symptoms overlap with several other digestive disorders. So monitoring your symptoms and getting a lactose intolerance test done is the only way to diagnose accurately.