How do doctors check for irritable bowel symptoms? what are the common symptoms?

IBS symptoms: Common symptoms of irritable bowel syndrome include: diarrhea or constipation (which may alternate); feeling bloated, cramping, abdominal pain, passing gas & mucus in stool. Diagnosis is made if there is pain or discomfortt for at least 12 weeks. There must be at least 2 additional sxs such as mucus in stool, bloating, , straining due to sense that bowels are not emptying properly. See below.

And rule out other: The symptoms of irritable bowel syndrome may also occur with celiac disease and carcinoma of the colon. These should be ruled out before accepting pain, diarrhea, constipation, etc. As irritable bowel syndrome, which is a diagnosis that is made when all other possibilities are ruled out.