Yes, a stool-based test can potentially detect colon problems. For instance, a stool DNA test can look for signs of colon cancer using a stool sample. A stool DNA test examines your sample for cells and then checks for changes in that cell's genetic material or DNA. Some DNA changes can indicate the presence or probability of cancer. Although doctors consider colonoscopy the best option for testing for colorectal cancer, a stool test also provides valuable insights into your colon health. It can detect blood in your stool, for example.