Positives

• Patients describe lactulose as a tolerable preparation for at-home SIBO breath testing, with the advantage that it samples the entire small intestine, per a PMC review of breath testing.
  
  
• Long COVID GI patients have begun routinely receiving lactulose breath testing as part of evaluation for post-viral SIBO and methane overgrowth, per a Long COVID Clinic testing description.
  
  

Negatives

• Patients commonly report cramping, bloating, and the urgent need to use the bathroom during the 3-hour test because lactulose itself acts as an osmotic laxative, per Jackson County Gastroenterology's procedure page.
  
  
• A meta-analysis cited just 42% sensitivity, meaning patients can have a falsely negative result and remain symptomatic, per the same PMC review.
  
  

Hurdles & Side Effects

• Patients have to do a strict prep diet for 24-48 hours before testing and avoid antibiotics, probiotics, and prokinetics for weeks beforehand, per a Rupa Health test description.
  
  
• Insurance often does not cover the test, leaving patients to pay several hundred dollars out of pocket, per SIBO Center's testing overview.