screening test for colorectal cancer

What tests are used to screen people for colorectal cancer? 
 
People who have any risk factors for colorectal cancer should ask their doctor when to begin screening for colorectal cancer, what tests to have, and how often to schedule appointments. Doctors may suggest one or more of the tests listed below as a part of regular checkups. 

A fecal occult blood test (FOBT) is a test for hidden blood in the stool. This test has been proven to reduce the death rate of colorectal cancer.
A sigmoidoscopy is an examination of the rectum and lower colon with a lighted instrument.
A colonoscopy is an examination of the rectum and entire colon with a lighted instrument.
A double contrast barium enema is a series of x-rays of the colon and rectum. The x-rays are taken after the patient is given an enema with a white, chalky solution that contains barium to outline the colon and rectum on the x-rays.
A digital rectal exam (DRE) is a test in which the doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas.
Virtual Colonoscopy can be performed with computed tomography (CT), sometimes called a CAT scan, or with magnetic resonance imaging (MRI).