Colonoscopy Coding Overview

Aug 27, 2025

Overview

This lecture covers colonoscopy coding, focusing on documentation, code selection, and key differences between screening and diagnostic procedures, with attention to current guidelines and common coding practices.

Colonoscopy Intent & Setting

  • Colonoscopies are primarily performed in Ambulatory Surgery Centers (ASCs) or hospitals.
  • Guidelines and documentation may differ slightly between ASCs and hospitals but are largely similar.
  • Always determine the intent of the colonoscopy: screening (preventative) vs diagnostic (symptoms present).

Screening vs Diagnostic Colonoscopies

  • Screening colonoscopies are typically recommended starting at age 45, earlier for high-risk individuals.
  • Diagnostic colonoscopies are performed when symptoms (e.g., pain, bleeding, suspected disease) are present.
  • Coding requires both a CPT/HCPCS procedure code and an ICD diagnosis code supporting the procedure's intent.

Common Codes for Colonoscopy

  • ICD Codes for Screening:
    • Z12.11 — Encounter for screening for malignant neoplasm of the colon.
    • Z85.038 — Personal history of other malignant neoplasm of the large intestine.
    • Z86.010 — Personal history of colonic polyps.
    • Z80.0 — Family history of malignant neoplasm of digestive organs.
  • HCPCS Codes (Medicare patients):
    • G0121 — Colonoscopy, not high risk.
    • G0105 — Colonoscopy, high risk.
    • G0104 — Flexible sigmoidoscopy.
  • CPT Codes:
    • 45378 — Flexible colonoscopy, diagnostic.
    • 45330 — Flexible sigmoidoscopy, diagnostic.

Conversion and Modifiers

  • If a screening colonoscopy becomes diagnostic (e.g., polyps are found/removed), code as diagnostic.
  • Use modifier PT (Medicare) for colorectal screening converted to diagnostic, modifier 33 (commercial payers) for preventive services.

Colonoscopic Removal Techniques & Coding

  • Use separate codes for different removal techniques (e.g., hot biopsy vs snare).
    • 45384 — Removal with hot biopsy forceps.
    • 45385 — Removal with snare technique.
  • Verbiage clues: "hot biopsy" for 45384; "snare loop," "in block," "piecemeal" for 45385.
  • Use multiple codes if multiple techniques are used in one procedure.

Other Common Colonoscopy CPT Codes

  • 45380 — With biopsy, single or multiple.
  • 45381 — With directed submucosal injection (e.g., tattooing).
  • 45382 — With control of bleeding, any method.
  • 45388 — With ablation of tumor.
  • 45390 — With endoscopic mucosal resection.

Documentation & Coding Tips

  • Always code to the intended extent of the procedure if incomplete; use modifiers for incomplete procedures.
  • Use BAT (Bubble-Highlight-Annotation) technique for marking key code descriptions in your CPT manual for faster, more accurate coding.
  • Z-codes indicating reason for encounter are usually sequenced first if they explain why the procedure is performed.
  • For suboptimal prep, consider code Z91.19.

Key Terms & Definitions

  • Screening Colonoscopy — Done to detect disease in asymptomatic patients.
  • Diagnostic Colonoscopy — Performed to investigate symptoms or findings.
  • Modifier PT — Indicates colorectal cancer screening converted to diagnostic for Medicare.
  • Modifier 33 — Preventive services for most commercial payers.
  • BAT Technique — Bubble, highlight, annotate in CPT manual for clarity.

Action Items / Next Steps

  • Review appropriate use of modifiers PT and 33.
  • Verify and memorize the most common colonoscopy and removal CPT/HCPCS/ICD codes.
  • Practice using the BAT technique on CPT codes relevant to GI/endoscopy procedures.
  • Check payer policies for screening age and high-risk definitions.