How Colon Tests are Done

The incidence of colon cancer in the United States has been on the rise in recent years. Younger patients are being diagnosed with colon cancer. Those with early-stage colon cancer tend to fare better than those who are diagnosed in the advanced stages of the disease. Hence, the importance of colon cancer screenings.

Colon cancer screenings detect the presence of malignant cancer cells in the colon before they start causing symptoms. With early detection and treatment, the prognosis for patients is excellent.

There are several types of tests that can be used to screen for colon cancer. Here, we will talk about the most commonly used colon tests and how they are performed.

Fecal Occult Blood Test (FOBT)

This test checks for hidden blood in the stool, which can be a sign of cancer. This can be performed at home, using a home test kit that your healthcare provider gives you. The test involves collecting a small sample of stool on a piece of toilet paper or in a container provided with the kit and then sending it to a laboratory for analysis.

Flexible Sigmoidoscopy

During the procedure, a long, flexible tube (sigmoidoscope) is inserted into the rectum and passed through the large intestine. It is called a sigmoidoscopy, because it examines the sigmoid part of the colon, which connects the large intestine to the colon and rectum. The sigmoidoscope allows the doctor to view the inside of the intestine and look for any abnormal growths or polyps, which can be removed during the procedure. A flexible sigmoidoscopy only examines the lower part of the colon and rectum. You will be sedated for the test, so you won’t feel any pain and will remain in a semi-conscious state.

Preparing for a flexible sigmoidoscopy generally involves fasting for several hours before the procedure and taking laxatives or enemas to clean out the lower part of the intestine. You may be asked to drink clear liquids only on the day of your exam.


This is considered the gold standard screening method, because it allows doctors to directly visualize the entire length of the large intestine and find any abnormal growths in the colon lining and remove them if necessary. Your doctor will give you sedatives before the procedure to help you relax. Once you’re sedated, they will insert the tube and slowly guide it through the rectum and into the colon. As they move the tube along, they will pump air into the colon to get a better view.

The whole process usually takes 30-60 minutes. The doctor will be looking for any abnormal growths or polyps in the colon that could potentially turn cancerous down the line. If they find anything suspicious, they may take a biopsy (tissue sample) for further testing.

A colonoscopy requires preparation or a colon-prep beforehand to empty the bowel of its contents for better visualization of the large intestine.

Colon Testing in California

If you have concerning symptoms about your colon health, you can trust the board-certified gastroenterologists at Genensis Healthcare Partners with your screening and care. Each colon test has its advantages and disadvantages, and your GI specialist will help you decide on the best one for you. We will also design a customized treatment plan for you, should one be necessary.

Genensis Healthcare Partners has many locations throughout the state of California. To schedule an appointment with us, please call our GI clinic nearest you or use our convenient online appointment request form.