Revenue Cycle, Health Data

Best Practices for Accurate Colonoscopy Coding

The coverage landscape for colorectal cancer (CRC) screening has changed dramatically in the past several years. Laws and regulations at the state and federal level impact appropriate coding, which ultimately impacts patients. This is particularly important when it comes to cancer screening, as improperly coded claims may result in denied coverage and unexpected bills for patients. 

Colorectal cancer ranks second in cancer-related deaths for men and women. Unlike many other cancers, early detection through timely screening can prevent its progression. Early screening can distinguish between an early stage and late-stage diagnosis. At the latter stage, the disease becomes harder to treat. 

The Departments of Health and Human Services, Labor, and Treasury, in conjunction with the Centers for Medicare and Medicaid Services, have waived out-of-pocket costs for colonoscopies after abnormal non-invasive colorectal cancer screenings. This applies to patients with Medicare, Affordable Care Act (ACA), and commercial insurance plans, with some exceptions. By eliminating the financial burden, a major obstacle to completing CRC screening is addressed.  

Patients at average risk for colorectal cancer have multiple screening modalities to choose from, including colonoscopy and non-invasive at-home options such as a fecal occult blood test (FOBT), a fecal immunochemical test (FIT), or a stool DNA test (Cologuard). However, if a patient chooses a non-invasive option and receives an abnormal result, they must have a colonoscopy to complete their screening. 

The revised policy on follow-up colonoscopies is a significant victory for patients and has the potential to save lives. However, it is essential to ensure accurate coding and billing, so patients fully benefit from this change. 

For commercial and Medicaid patients, modifier 33 (preventative services) should be added to each screening colonoscopy Current Procedural Terminology (CPT) code submitted on the claim. If modifier 33 is not added, the colonoscopy will not be recognized as a screening service and the patient will be inappropriately billed. 

For Medicare, modifier KX (requirements specified in the medical policy have been met) should be applied with Healthcare Common Procedure Coding System (HCPCS) code G0105 or G0121 for screening colonoscopy for patients following a non-invasive, stool-based test. If polyps are removed, the appropriate CPT code should be used with modifier PT (colorectal cancer screening test; converted to diagnostic test or other procedure).  

To support health information professionals, Fight Colorectal Cancer (Fight CRC) and the American Gastroenterological Association (AGA) created a resource to provide policy background and important coding information for the recent changes on follow-up colonoscopy coverage to supplement the coding resources AHIMA has developed for CRC screening.  

For additional resources on this policy change, visit Fight CRC’s website or AGA’s website.  


Molly McDonnell is the director of advocacy for Fight Colorectal Cancer, a national patient advocacy organization that serves the colorectal cancer community through informed patient support, impactful policy change, and breakthrough research endeavors. 

Leslie Narramore, MPA, is senior director of regulatory affairs for the American Gastroenterological Association, an organization made up of more than 16,000 members from around the globe who are involved in all aspects of the science, practice, and advancement of gastroenterology.