Diagnosis of Colon Polyps

How do doctors diagnose colon polyps?

Doctors can find colon polyps only by using certain tests or procedures, such as a colonoscopy or imaging study. Your doctor may first take a medical and family history and perform a physical exam to help decide which test or procedure is best for you.

For example, your doctor may ask if you have any symptoms. He or she may also ask if you have a family history of colon polyps or colorectal cancer. After taking a medical and family history, your doctor may perform a physical exam.

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Your doctor can find colon polyps only by using certain tests or procedures.

Tests and procedures

  • Flexible sigmoidoscopy. For a flexible sigmoidoscopy, a trained medical professional uses a sigmoidoscope—a flexible, narrow tube with a light and tiny camera on one end—to look inside your rectum and lower colon. Flexible sigmoidoscopy can show irritated or swollen tissue, ulcers, polyps, and cancer.
  • Colonoscopy. During a colonoscopy, a trained medical professional uses a long, flexible, narrow tube with a light and tiny camera on one end, called a colonoscope, to look inside your rectum and colon. Colonoscopy can show irritated and swollen tissue, ulcers, polyps, and cancer.
  • Virtual colonoscopy. Virtual colonoscopy uses x-rays and a computer to create images of your rectum and colon from outside the body. Virtual colonoscopy can show ulcers, polyps, and cancer. Doctors can’t remove polyps during virtual colonoscopy.
  • Lower gastrointestinal series. For a lower gastrointestinal (GI) series, a doctor uses x-rays and a chalky liquid called barium to view your large intestine. The barium will make your large intestine easier to see on an x-ray. A lower GI series is also called a barium enema.
September 2017
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.