Breath test for SIBO and intolerances

These tests share the same preparation. They measure the hydrogen and methane produced by your gut bacteria when digesting food.

• Medication (Weeks before): Do not take antibiotics or probiotics for 4 weeks before the test. Avoid using prokinetics (medicines that speed up gut transit) or laxatives for a week before. Furthermore, the test shouldn't be done if you've had a colonoscopy within the past 30 days.
• Strict diet (24 hours before): This is the most crucial and restrictive rule. For the entire day before the test, your diet must be entirely free from dietary fiber and fermentable sugars. Permitted foods are limited to grilled or boiled chicken, turkey, fish or beef, eggs, boiled white rice, olive oil, salt, and water. Forbidden foods include anything containing dairy, fruit, vegetables, legumes, bread, pasta, cold cuts/sausages, sweets, chewing gum, sodas, and alcohol.
• Overnight fast (12 hours before): Keep an absolute fast from solid food for 12 hours leading up to the appointment. You may only drink plain water.
• Oral hygiene the day of the test: Thoroughly brush your teeth upon waking. Many labs also require using a chlorhexidine mouthwash (available at pharmacies) right before leaving the house to clear out mouth bacteria that might alter the first reading. Avoid using denture adhesives on this particular day.
• Habits and exercise: Refrain from smoking from the night prior and during the 3 hours the test lasts at the clinic. Don't engage in strenuous physical exercise the day before or the same morning, since hyperventilation affects gas measurement.

Step-by-step process at the clinic: This is a lengthy test, requiring patience. Set aside plenty of time because it takes between 2 and 3 hours (depending on hospital protocols).

1. Baseline reading: Upon arriving, you will blow into a first tube to gauge your fasting gas levels (this explains why the strict fiber-free diet is so vital, ensuring we start from zero).

2. The drink (the substrate): You will be given a glass of water mixed with the specific sugar you are being tested for (Lactose, Fructose, Sorbitol, Lactulose, or Glucose). It usually tastes quite sweet.

3. Repeated readings: From then on, you will need to blow into a new tube every 15 or 30 minutes (you'll be notified), until completing the full 2 or 3 hours of the test.

4. Absolute rest: During this time, stay seated in the waiting room at rest, refraining from eating, drinking (only tiny sips of water if authorized), sleeping, or exerting physical effort.

5. Tracking symptoms: Should you experience genuine discomfort during the test (bloating, abdominal cramps, gas, stomach rumblings, urgent need for a bathroom), please inform the staff so they log it; this data is critical for the final diagnosis.