no not really but i am not sure what kind of stool test your doctor has ordered. a simple stool test for occult blood would certainly be appropriate and it is easy and inexpensive. remember that a colonoscopy is looking for pre-cancerous and cancerous polyps (as well as other colon problems). many of these can cause occult (hidden) blood to be mixed in with the stool and go unnoticed. if this stool test is just for blood then do it. if this stool test is a different test then your medical provider has an obligation to justify it to you.
is a stool test necessary to be done before having a colonoscopy done