Computed Tomography Colonography (CT Colon/Rectum) with IV Contrast and Air-Contrast Protocol
A CT scan of the large intestine that uses intravenous contrast and rectal air to evaluate the colon and rectum for polyps and other abnormalities.
["This imaging test uses CT and contrast to examine the colon and rectum for polyps, cancer, and other bowel abnormalities."]
Key facts at a glance
- LOINC
- 72531-7
- Short code
- CT Colon+Rect W contr IV+Air contr PR
- Synonyms
- CT Colon+Rect W contr IV+Air contr PR
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ct
- CPT
- 86592
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
CT colonography is an imaging test of the large intestine. It uses computed tomography, intravenous contrast, and air or gas introduced through the rectum to create detailed pictures of the colon and rectum without inserting a conventional scope.
Why might I need this test?
This test may be used to investigate blood in the stool, changes in bowel habits, unexplained abdominal symptoms, or a suspected colon mass. It may also be used for screening when colonoscopy is not completed or is not preferred.
How is the test performed?
After the bowel is prepared, a technician places an IV line and gives contrast by vein. Air or gas is introduced through a small tube placed in the rectum, and the CT scanner takes detailed images while you lie still.
How do I prepare for the test?
Your bowel must be thoroughly cleaned, usually with a laxative and restrictions on food and liquids. Follow the exact instructions from the imaging center, and tell the care team about any contrast allergy, kidney disease, pregnancy, or medications such as metformin.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal findings may indicate polyps, colorectal cancer, diverticular disease, inflammation, a mass, or a bowel obstruction. Some findings may require colonoscopy or another follow-up test for direct examination or tissue sampling. Even a normal CT colonogram may not detect every small or flat lesion, so follow-up recommendations should be discussed with your clinician.
Short name
CT colonography with IV and air contrast
Frequently asked questions
Is CT colonography the same as a colonoscopy?
Is the test uncomfortable?
What should I do if the result is abnormal?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy