Screening Flexible sigmoidoscopy

Am I correct G0104 can be done every 4 years for non high risk and high risk patients. Why would you do a flex on a high risk patient when you can do a colonoscopy on a high risk patient every 2 years. I'm lost.

re: Screening Flexible sigmoidoscopy

The CMS reference guide can be downloaded here:

http://codapedia.com/article_112_Preventive-Medicine-Services-for-Medicare-Patients.cfm

If that doesn't help, take a look at the Medicare Claims Processing Manual, chapter 18.