Screening Colonoscopies versus Diagnostic Colonoscopies

Medicare covers screening colonoscopies once every 24 months for high-risk patients and for patients not at high risk, once every ten years (120 months), or four years (48 months) after a previous flexible sigmoidoscopy.

Screening colonoscopy indicated for patients:

  • Aged 50-85 years
  • Asymptomatic
  • Average colorectal cancer risk

When a screening colonoscopy transitions to a diagnostic colonoscopy, medical records must indicate:

  • Medical reasonableness, necessity, and frequency of each diagnostic service supplied
  • Colonoscopy report must describe maximum depth of penetration, description of abnormal findings and any procedures performed from the findings (e.g., biopsy).
  • Append -PT modifier to CPT indicating screening colonoscopy switched to diagnostic colonoscopy.

Diagnostic colonoscopy indicated for patients:

  • Abnormality determined by radiology exam consistent with colonic lesion
  • Abnormal oncology colorectal screening or stool-based DNA test
  • Unexplained gastrointestinal bleeding:
    • Hematochezia not from rectum or perianal source
    • Melena of unknown origin
    • Presence of fecal occult blood
    • Unexplained iron deficiency anemia
  • Clinically significant diarrhea of unexplained origin
  • Needs evaluation of acute colonic ischemia or ischemic bowel disease
  • Needs evaluation due to streptococcus bovis endocarditis when source determined to be colonic origin
  • Clinical suspicion of inflammatory bowel disease
  • Known chronic inflammatory bowel disease of the colon when a more precise extent of disease determination will influence treatment
  • Surveillance of Crohn’s colitis or chronic ulcerative colitis to rule out colorectal cancer
  • Surveillance of colonic neoplasia


Last Updated Oct 21 , 2022