Thank you for the query.
When blood and mucus in stool appears, colon cancer
should be ruled out. If you also suffer from constipations or/and diarrhea, lost of weight colonoscopy
should be performed. If your pain is located on the lower left side of abdomen there is a chance that this is diverticulitis(however CT would tell that you have diverticles). Blood and mucus in stool can be also caused by inflammatory bowel diseases (like Crohn`s disease) which can also be ruled out by colonoscopy.
If you abdominal pain
is located in upper middle abdomen and your blood in stool
is dark, you may suffer from peptic ulcer
(according to often pain killers usage). To rule this one out, upper GI endoscopy should be performed.
If it is about WBC increased level it simply means that somewhere in your body there is an infection. It might be caused by all previously mentioned conditions so basically it does not rule anything out.
Hope this will help.