SIBO Breath Test

How to do the Test & Reading the Test

How to do the SIBO Breath Test:

Preparation phase:

  • 2-4 weeks before test:

  • Wait 4 weeks from your last dose of antibiotics, colonoscopy or barium enema.

  • Wait at least 2-4 weeks from your last dose of antifungals, Pepto-Bismol TM or herbal/ natural antimicrobials

  • 7 days before the test:

  • Avoid the use of laxatives, stool softeners, and or stool bulking agents as well as antacids containing aluminum or magnesium hydroxide. (Magnesium citrate etc is fine)

  • 24 hours before the test:

  • The purpose of the prep diet is to get a clear reaction to the test solution by reducing fermentable foods the day before. In some cases, two days of prep diet may be needed to reduce baseline gases to negative.

  • Foods you can eat before you start your 12 hour fast:

    • Baked or broiled chicken, fish, turkey (salt and pepper only), white bread (only), plain steamed white rice, eggs, clear chicken or beef broth (not bone broth or bouillon) with no vegetable pieces, water, plain coffee, tea, no sugar/ artificial sweeteners or cream, oil, salt, and pepper.

    • Vegetarians may have tofu with salt and pepper.

    • Do not take probiotics.

  • 12 hours before the test

  • Don’t eat or drink anything other than water for 12 hours prior and during the test.

  • Do not take non essential medications or supplements during the test.

  • Do not chew gum, eat candy or use mouthwash until the test is complete.

  • 1 hour before the test:

  • No smoking (includes second hand smoking), for at least 1 hour before or at any time during breath test.

  • No sleeping or vigorous exercise for at least 1 hour before or at any time during the breath test.

  • Doing the test

  • Do not use toothpaste.

  • Brush teeth and tongue without toothpaste. Rinse with water.

  • Write your full name, DOB, Gender, DOC, and tube number 1-6/8.

  • Take your first tube collection. Record collection time.

  • 1 breath before lactulose; exhale normally until tube fills with condensation. Tip, exhale slightly before you start to fully exhale and bring the apparatus to your mouth.

  • Stir lactulose solution into 8 oz water and drink entire amount within 5 minutes. Do not drink water for the following one hour.

  • Do another breath test in 20 minutes and every 20 minutes after that, until 6-8 tubes are used.

The classic positive for SIBO has been considered to be a double peak, with the first peak representing the SIBO and the second peak representing the normal large intestine bacteria. This is an infrequent presentation in our experience. More frequently we see one peak that rises highest in the third hour, representing distal SIBO and then the normal large intestinal (LI) bacteria.

Reading your SIBO Breath Test:

Hydrogen (H), Methane (M), Hydrogen Sulfide (HS)


What we are looking for:

If H <20 ppm= neg, H >40 ppm= definite pos for Hydrogen

If M <3 ppm=neg, M >12 ppm= definite pos for Methane

H and M should increase quiet rapidly after drinking the drink in the first 100-120 minutes.

A flatline test: possibly hydrogen sulfide.