CPT Codes for Screening Colonoscopy
For a screening colonoscopy in an average-risk patient, use CPT code 45378 (colonoscopy, flexible; diagnostic, including collection of specimen(s) by brushing or washing, when performed) with modifier PT (colorectal cancer screening test; converted to diagnostic test or other procedure) if polyps are found and removed, or G0121 (colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk) for Medicare patients with no findings.
Primary Screening Codes
The specific CPT code depends on what occurs during the procedure and the patient's insurance type:
For Medicare Patients
- G0121: Screening colonoscopy for average-risk patients with no polyps found 1
- G0105: Screening colonoscopy for high-risk patients 1
- 45378 with modifier PT: When a screening colonoscopy is converted to diagnostic (e.g., polyp removal) 1
For Non-Medicare Patients
- 45378: Diagnostic colonoscopy, which is often used for screening when no specific screening code applies 1
- Add modifier 33: Preventive service modifier to indicate screening purpose 1
Key Coding Considerations
The code changes based on findings and interventions performed during the procedure:
- If polyps are biopsied or removed during a screening colonoscopy, the procedure converts from screening to diagnostic, requiring different coding 1
- For colonoscopy with polypectomy, use codes 45384 (snare technique) or 45385 (hot biopsy forceps) with appropriate modifiers 1
- Complete examination to the cecum with adequate visualization is required for proper coding 1
Documentation Requirements
Proper documentation must include:
- Indication for the procedure (screening vs. diagnostic) 1
- Cecal intubation confirmation 1
- Quality of bowel preparation 1
- Any polyps found, their size, location, and method of removal 1
- Withdrawal time (should be ≥6 minutes for adequate inspection) 2
Common Pitfalls
Avoid these coding errors:
- Using screening codes when the patient has symptoms or positive prior testing—these are diagnostic, not screening procedures 1
- Failing to document cecal intubation, which is required for full reimbursement 1
- Not converting to diagnostic codes when polyps are removed during screening 1
- Using annual FOBT codes in combination with screening colonoscopy, which is inappropriate 1
Insurance-Specific Nuances
Medicare and private insurers have different coverage policies that affect coding. Medicare covers screening colonoscopy every 10 years for average-risk patients starting at age 50 (or 45 for African Americans per some guidelines), while high-risk patients may qualify for more frequent screening 3, 4. Private insurers typically follow similar patterns but may have specific code requirements, so verify payer-specific guidelines before billing.