The CMS - that would be the folks who administer Medicare - has proclaimed that the Barium Enema is an important preventative service and should be free to all Medicare recipients.

This procedure, which had its heyday a few decades ago, involves making an image of the colon by forcing a solution of barium - a somewhat toxic element - into the anus and then exposing the patient to x-rays. It has been replaced by the sigmoidoscopy - a much more humane procedure that involves forcing a flexible plastic tube equipped with a camera up into the anus.

The procedure is no longer used for diagnosis of colorectal cancer because: "If you found anything you would still have to do a sigmoidoscopy to see whatever it was you found," to quote Wonks Anonymous doctor.

So we have one more rule, designed to make sure that we charge fees for medical services that consumers should be discouraged from using while we charge no fees for the "good" medical services that we want to encourage people to get.

Maybe we should try prepaid group practices. Pay integrated medical groups a fixed payment to provide care. Get rid of most point of service payments and trust the doctors to decide which care is effective and efficient.