45378

Colonoscopy, flexible, diagnostic

A diagnostic colonoscopy is a medical procedure that uses a long, flexible tube (colonoscope) with a camera to visually examine the entire length of the large intestine (colon and rectum). It is performed to identify abnormalities such as polyps, inflammation, bleeding, diverticulosis, or other changes in the mucosal lining. Tissue samples (biopsies) may be collected during the procedure for histopathological analysis, but no therapeutic intervention (e.g., polyp removal) is performed for this specific code.

Clinical Indications

  • Evaluation of unexplained gastrointestinal bleeding (e.g., hematochezia, melena, positive fecal occult blood test, iron deficiency anemia)
  • Investigation of changes in bowel habits (e.g., chronic diarrhea, unexplained constipation, alternating bowel habits)
  • Evaluation of chronic abdominal pain or unexplained weight loss without a clear etiology
  • Surveillance for patients with a personal history of colorectal polyps or colorectal cancer (when no therapeutic intervention is planned or performed)
  • Follow-up for abnormal imaging studies (e.g., CT scan, barium enema) suggesting colonic pathology
  • Diagnosis, assessment of extent, or surveillance of inflammatory bowel disease (Crohn's disease, ulcerative colitis)
  • Evaluation of a family history of colorectal cancer or polyps (for diagnostic, not screening purposes when G-codes are not applicable)

Procedure Steps

  1. Patient receives instructions for bowel cleansing preparation prior to the procedure to ensure clear visualization.
  2. Administration of sedation or anesthesia to ensure patient comfort and cooperation.
  3. The colonoscope is gently inserted into the rectum and advanced through the sigmoid colon, descending colon, transverse colon, ascending colon, and into the cecum, attempting complete examination of the entire colon.
  4. The physician systematically inspects the mucosal lining of the colon and rectum during insertion and withdrawal of the scope.
  5. Any identified abnormalities (e.g., polyps, inflammation, strictures, diverticula, lesions) are documented.
  6. Biopsy specimens may be collected from suspicious areas using forceps or brushes, but no therapeutic removal (e.g., polypectomy) is performed under this code.
  7. The colonoscope is slowly withdrawn while maintaining careful visual inspection.
  8. Post-procedure monitoring in a recovery area until the patient is stable.

Coding Guidelines

  • Code 45378 is strictly for diagnostic colonoscopies where the primary intent is examination and identification of abnormalities, including the collection of specimens (biopsies) by brushing or washing.
  • If any therapeutic intervention is performed during the same session (e.g., polypectomy, mucosal resection, ablation), only the more comprehensive therapeutic CPT code should be reported, as 45378 is typically bundled into therapeutic procedures.
  • This code includes the collection of specimens by brushing or washing. It is not separately billable when performed with 45378.
  • Carefully distinguish between diagnostic colonoscopies (45378) and screening colonoscopies (e.g., G0121, G0105 for Medicare). While 45378 can be used for screening by some commercial payers, appropriate screening diagnosis codes (e.g., Z12.11) and modifiers (e.g., -33 for preventive service) should be used.
  • Modifier 52 (Reduced Services) may be appended if the procedure is intentionally terminated before reaching the splenic flexure due to medical necessity (e.g., inability to advance the scope due to stricture or severe angulation).
  • Ensure documentation clearly supports the medical necessity for the diagnostic colonoscopy and details all findings and procedures performed, including the extent of the examination.
  • When a colonoscopy is performed following an incomplete colonoscopy, refer to payer-specific guidelines for modifier usage (e.g., -53 for discontinued procedure by physician decision or -73/-74 for facility reporting).

Associated ICD-10 Codes