Sunday, June 26, 2022

The Difference Between a Screening and Diagnostic Colonoscopy.

Many patients are confused by the difference between a screening and a diagnostic colonoscopy.  While the actual procedure is the same, the distinction between the two depends on why the colonoscopy is being done.  While you might think that I am wading into a sea of nonsense and absurdity, I am offering you a glimpse of the rational and reasonable world of medical insurance!  Try to follow along.

Here’s a primer.

A screening exam means that you have no symptoms or relevant laboratory or x-ray abnormalities that justify a colonoscopy.  Consider this to be a simple check-up for your colon.  You are being screened to determine if you have a hidden abnormality or lesion.  Get it? 

A diagnostic exam means that the doctor is investigating an existing or suspected abnormality. A medical condition is under consideration and a colonoscopy is advised to investigate.   For example, if you have bowel symptoms, weight loss, blood in the stool, a personal history of colon polyps or a CAT scan that shows an abnormal intestine, then your colonoscopy will be considered diagnostic, not screening.   Get it? 

Large Intestinal in diameters

Diagnostic or Screening?
It's a Question of Motive.

Why does this even matter?   Do not expect that my response will make sense to you, since it makes no sense to me, and I’ve been in the business for a few decades.

In general, most insurance companies will cover screening colonoscopies fully, but most diagnostic colonoscopies will be subject to deductibles and co-insurance.  In other words, even though a diagnostic colonoscopy is the exact same test in every way as a screening exam, the diagnostic version may cost patients more.  Make sense?  If so, please leave a comment so you can explain it to me. 

And, permit me to offer an example when the absurd transforms into the insane.  If a polyp is found on a screening colonoscopy, then the procedure will be changed from a screening to a diagnostic colonoscopy automatically!  So, such a patient who believed that his screening procedure will be fully covered, may have a $urpri$e awaiting him.  The federal government's position that even if a polyp is a discovered, this should not impact patients financially, although not all insurance carriers are on board with this.

Before you have your colonoscopy, it is important to contact your insurance company about your benefits so that you understand the coverage prior to undergoing the procedure.  Ask if your financial obligation changes if a polyp is removed or any biopsies are taken.   I always advise that you write down the name of the insurance company representative and make some notes of the conversation just in case. 

On occasion, patients will contact us after the fact and ask us to change our code from diagnostic to screening, for reasons that readers will now understand.   While we may sympathize with their plight, we are not in the business of altering medical records or otherwise gaming the system. Such behavior would risk a whistleblower turning me in.   


  1. Hrmm. Makes me wonder where CHEK2 falls on this. I've also been told that needing a colonoscopy after a Cologuard result makes it diagnostic and not a screening as well. Apparently a lot of folks have been surprised by the bill.

  2. @Pinata of Path. Appreciate your response. Yes, you are correct that a colonoscopy that follows a positive Cologuard or other abnormal stool test is a diagnostic study, although GI societies are trying to address this. Welcome to the Theater of the Absurd!

  3. Progress is just around the corner!