How to read colonoscopy results

If you or a loved one recently had a colonoscopy (koe-lun-OS-kuh-pee), you may be wondering what the results mean. This guide can help you understand the common terms and findings in your colonoscopy report. But it’s important to review your specific results with your healthcare team to get a complete explanation and personalized recommendations.

A colonoscopy lets your healthcare professional look directly at the inside of your colon and rectum to check for changes or signs of disease. The exam can reveal:

• Polyps. These are small growths on the lining of the colon that can be precancerous or noncancerous, also called benign. Most polyps are harmless. But removing polyps during colonoscopy helps prevent colorectal cancer.
• Cancer. A colonoscopy can find signs of cancer, such as areas on the colon lining that look uneven, swollen or have open sores.
• Inflammation. Areas of redness, swelling or sores may indicate irritation or an inflammatory condition, such as colitis. The appearance and location of inflammation can help determine whether it’s due to infection, inflammatory bowel disease or another cause.
• Bleeding. The test can identify where bleeding is coming from inside the colon. Bleeding is often caused by ulcers, hemorrhoids, fragile blood vessels or areas of inflammation. Finding the source of bleeding helps doctors treat the problem and prevent further blood loss.
• Diverticulitis. A colonoscopy can show small pouches, called diverticula, that form in the wall of the colon. These pouches are common and usually harmless. If they become inflamed or infected, the condition is called diverticulitis. A colonoscopy is often done after recovery from diverticulitis to rule out other causes of symptoms.
• Hemorrhoids. The procedure can show swollen veins in the rectum or anus that may cause pain, itching or bleeding. These are common and often related to straining, constipation or pregnancy. Finding hemorrhoids during a colonoscopy helps rule out other potential causes of rectal bleeding.
• Parasites. In uncommon cases, a colonoscopy may incidentally reveal other issues, such as visible parasites. However, these findings are unusual. Stool tests are typically used to diagnose parasitic infections.

• Other signs of digestive disease. The exam may show changes that suggest inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis. Colonoscopy allows doctors to view inflammation directly and take small tissue samples, called biopsies, to confirm the diagnosis and guide treatment.

  If you have diarrhea, inform the healthcare professional who is doing the colonoscopy. The health professional may consider assessing for microscopic colitis. This condition causes a type of inflammation only seen from a biopsy, as the colon lining often appears healthy.

  A colonoscopy also can help rule out other causes of symptoms that overlap with irritable bowel syndrome (IBS) or celiac disease. However, these conditions are not diagnosed by colonoscopy.

If necessary, polyps or small pieces of tissue can be removed during the procedure. These samples are then examined in a laboratory to confirm or rule out certain conditions.

A virtual colonoscopy, also called CT colonography, uses computerized tomography (CT) imaging to create detailed pictures of the colon and rectum. This test can detect many of the same findings, such as polyps, growths or narrowing, but it does not allow tissue removal or biopsy during the same exam.

If a virtual colonoscopy shows anything irregular, a standard colonoscopy is usually needed to confirm the findings and remove any polyps for testing.

Your colonoscopy report includes several key sections that describe what happened during the exam and what it means for you.

• Procedure summary. This section explains why the exam was done, how well the bowel was cleaned out, and whether the healthcare professional reached the beginning of the colon, called the cecum. A complete view of the colon helps ensure accurate results.
• Findings. The doctor records what was seen during the procedure, including the presence of polyps, inflammation, bleeding or other changes in the lining of the colon.
• Pathology results. Tissue samples may be removed to examine under a microscope. The number of samples can range from one to several, depending on what is seen during the procedure. This section lists what the laboratory found when the tissue was examined under a microscope.
• Recommendations. This part outlines next steps, such as when to return for your next colonoscopy or whether lifestyle changes or additional tests are advised. If tissue samples were taken during the procedure, final recommendations may not be available until the pathology results are complete. It’s important to review the recommendations with the healthcare professional who ordered your colonoscopy. If you need more guidance or follow-up, you may be referred to a doctor who treats digestive issues, called a gastroenterologist, for further care.

High-quality reports always document how well the bowel was cleaned, whether the scope reached the beginning of the colon, and details about anything irregular or any growths that were found. These details help your care team understand how accurate your results are and guide the next steps in your care. Colonoscopy quality is carefully monitored to ensure every exam meets professional standards. Healthcare institutions track measures such as how often polyps are found, how long the doctor spends examining the colon, and how often the entire colon is successfully viewed.

You can review your report to understand the main findings, but interpreting what they mean for your health should always involve your healthcare team. Discuss your findings with your care team to understand whether you are considered at low, moderate or high risk and when your next colonoscopy should be scheduled.

Your colonoscopy report may include several terms that describe what was seen and what those findings mean. Knowing how to interpret these terms can help you understand your results before discussing them with your healthcare team.

• Normal results. A normal colonoscopy means the entire colon was seen clearly and no growths, inflammation or other unusual changes were found. After a high-quality exam with normal results, most adults at average risk can wait about 10 years before their next screening.
• Abnormal results. An abnormal result means something was found, such as polyps, inflammation or bleeding. The number, size and type of these findings determine when the next colonoscopy should be scheduled.
• Positive findings. A positive result means that the doctor identified an irregularity — for example, a polyp, inflammation or precancerous tissue. This doesn’t necessarily mean cancer but may require closer monitoring or treatment.
• Negative findings. A negative result means that nothing irregular was detected or that biopsy samples showed no cancerous cells or cell changes, called dysplasia. These results are generally reassuring. And they often result in longer intervals between colonoscopies.
• Nonspecific inflammation. This describes mild irritation or redness without a clear cause, often related to infection or bowel preparation.
• Chronic inflammation. This refers to ongoing irritation that may indicate a long-term condition such as ulcerative colitis or Crohn’s disease.

Polyps are a common finding. Studies show that polyps are detected in about 30% to 50% of colonoscopies in adults, depending on age, sex and screening history.

Adenomas, also called adenomatous polyps, are the most common precancerous type of polyp found during colonoscopy. About two-thirds of precancerous polyps fall into this category, and they can turn into a type of cancer called adenocarcinoma if they aren’t removed.

• Tubular adenoma. This is the most common type of precancerous polyp. It generally has the lowest risk.
• Villous or tubulovillous adenomas. These polyps have a higher chance of developing into cancer, so follow-up is sooner.

Not all polyps found during a colonoscopy are adenomas. Your report may mention other types of growths, which differ in how they look and how likely they are to become cancerous.

• Hyperplastic polyps. These small, noncancerous growths are most often found in the lower colon or rectum. They are considered low risk and generally do not require earlier follow-up unless they are large (10 millimeters or more) or located higher in the colon.
• Sessile serrated lesions (SSLs). These flat or slightly raised growths usually appear in the upper colon and can be difficult to see. Although most are benign, larger SSLs or those with cell changes, called dysplasia, have a higher potential to develop into colorectal cancer. Follow-up timing is similar to that for advanced adenomas.
• Traditional serrated adenomas (TSAs). These less common serrated polyps also carry a higher cancer risk. Follow-up is recommended on the same schedule as follow-up for advanced adenomas.
• Inflammatory polyps. These noncancerous projections are linked to chronic inflammation of the colon. They are often seen in conditions such as ulcerative colitis or Crohn’s disease. They do not increase cancer risk on their own but may signal active inflammation that requires ongoing care.
• Hamartomatous polyps. These rare polyps contain a mixture of normal tissue types and sometimes occur in hereditary syndromes such as Peutz–Jeghers or juvenile polyposis. People with these syndromes often need genetic counseling and specialized follow-up.

When polyps are removed, a pathologist examines them under a microscope to identify cellular changes, known as dysplasia. This describes how irregular the cells appear.

• Low-grade dysplasia. This indicates early or mild precancerous change. The cells show some unusual changes, but the risk of cancer is low. Most small tubular adenomas fall into this category and are managed with standard follow-up intervals.
• High-grade dysplasia. This describes more-advanced precancerous change. The cells look significantly more atypical, and the risk of developing cancer is higher. When high-grade dysplasia is found, closer surveillance and earlier repeat colonoscopy are recommended.

These features help determine how soon your next colonoscopy should be scheduled and guide long-term colorectal cancer prevention.

Finding and removing polyps is common and is one of the main ways that colonoscopy helps prevent colorectal cancer.

Some results are available right after the procedure, while others take more time.

• Initial findings. Your healthcare professional can usually tell you right after the colonoscopy what was seen during the exam, such as whether the colon looked healthy or if any polyps were removed.
• Pathology results. If tissue or polyps are sent to the laboratory for biopsy, it typically takes about 1 to 2 weeks for the results to come back. The exact timing can vary depending on the laboratory and whether special testing or additional review is needed.
• Follow-up. Your care team contacts you — often by phone, secure message or appointment — to explain the pathology report and discuss when you should return for your next colonoscopy. If the pathology report shows cancer, the next step involves referral to specialty care for staging and treatment planning. Early detection improves outcomes, and colorectal cancer screening can prevent cancer from developing.

Waiting for biopsy results can cause anxiety, but most findings are benign or show only early, treatable changes.