Definitely be persistent in getting the results. Call them and even consult your GI about the biopsy results. I had a colonoscopy back in 2011 when I was finding blood in my stool and having bloating problems. They took biopsies of the inflamed areas and I got a call saying they were clean non cancerous and they suspected ulcerative colitis was the issue. After that I continued to get worse and to the point where I was admitted to the hospital ( this was about two months following the procedure ). While at the hospital they found I had a bad C-diff infection. I was treated for it given flagyl, asacol, probiotics, and not sure if they had me on cipro through IV or not but I think they did. Afterwards I did better staying on probiotics but developed what is now crohns ( most likely from the c-diff infection trauma. Past two months I have been very sick with a flare up and was scheduled a colonoscopy and a endoscopy by my new GI doctor. He went through my past colonoscopy report and said they had a found a C-diff infection in the biopsy. I was surprised to hear this cause I was never told and the way they found out is when I got to the point where the infection was severe. I was told it was ulcerative colitis so I was trying to fix a C-diff infection by diet haahaha.