Lactose Intolerance Breath Test Instructions

↓ Download the instructions as PDF

What is the Hydrogen Breath Test for Lactose Intolerance?

The hydrogen breath test measures the amount of hydrogen in the breath. Normally, no hydrogen is detectable in the breath. However, undigested lactose leads to the formation of various gases including hydrogen, by bacteria in the colon. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In the test, the patient drinks a lactose-loaded beverage, and the breath is analyzed at regular intervals. Hydrogen in the breath means improper digestion of lactose. Certain foods, medications, and smoking can affect the test’s accuracy and may need to be avoided before the test.

Instructions for the Hydrogen Breath Test for Lactose Intolerance

• A baseline hydrogen level in your breath will be obtained at the time of your first visit. This requires only that you breathe into our machine. Formal testing will be performed at your next visit.
• On the day before testing, do not eat beans, bran, or high fiber cereals.
• Fast for 12 hours, with no food and only water to drink before testing.
• Do not smoke, sleep or exercise vigorously for at least ½ hour before, or at any time during testing.
• Please alert us about any recent antibiotic use and/or recent or current diarrhea as this may affect the result of the test.
• Three hours before your appointment, drink 12 oz of milk. It does not matter if you drink skim, 1%, 2% or whole milk, but you CANNOT drink Lactaid milk.

The result of the test will be given to you by the nurse or the physician before you leave our office.