How is ibs diagnosed? what sorts of tests do you have to go through?

Rome 3 criteria: Irritable bowel syndrome (ibs) is a condition associated w/ abdominal discomfort, altered /alternating stool pattern, accompanying nausea, bloating, gassiness. Often improved by stooling, ibs is defined by changes in perception of gut distension, motility, sensation. Diet & emotional stress may be a factor. Rome 3 diagnostic criteria must 1st rule out inflammation, ischemia, & infection. See doc.