Can irritatble bowel syndrome be found with a colonoscopy? if not how do they test for it?

No! IBS Clinical Dx: Ibs, like many dx, is made based on history of symptoms, sings/problems ; what factors ? vs ? the issues. Syndrome means combination of symptoms ; signs without clear basis; not a surprise because intestines controlled by brain stem 24/7 ; significantly affected by emotional states/experiences + current events. Meds, such as donnatal, (phenobarbital atropine hyoscyamine and scopolamine) which inhibit brain/intestine excitatory signals tends to calm.

No: There is no good test to diagnose irritable bowel syndrome. It is a diagnosis by exclusion and a characteristic history of bowel irregularity and cramping pains in the abdomen for which there is no obvious visible cause.