TABLE 3. Instructions that must be followed by patients before performing a breath test for SIBO.

Preparation	Explanation
Antibiotics should be avoided 4 weeks before BT	Alter H2 and CH4 composition on exhaled breath 38 .
Prokinetics drugs and laxatives should be avoided at least 1 week before BT.	In addition to modify microbiome production of gas, it can directly affect intestinal transit time and the substrate would get faster to the colon, increasing false positive results.
	If patient could not stand without these medications for a month before BT, it is strongly recommending the discontinuation at least for one week 39 .
Diet 24 hours before	Avoid fermentable complex carbohydrates and dairy products, including lactose and fructose diet 5 , 40 , 41 .
Fasting for 8 to 12 hours before
Avoid smoking the day before	Increase H2 levels on exhaled breath and gastric emptying time 42 , 43 .
Do not perform intensive physical activities the day before and during the test	Hyperventilation could inversely affect H2 levels 44 .
On the day of the test, it is recommended mouth washing with antiseptics	Avoid oropharyngeal flora contamination 35 .

SIBO: small intestinal bacteria overgrowth; BT: breath test; H2: hydrogen; CH4: methane.