Cologuard is a screening test for colon and rectal cancer.

The colon sheds cells from its lining every day. These cells pass with the stool through the colon. The cancer cells may have DNA changes in certain genes. Cologuard detects the altered DNA. The presence of abnormal cells or blood in the stool may indicate cancer or precancer tumors.

How the Test is Performed

The Cologuard testing kit for colon and rectal cancer must ordered by your health care provider. It will be sent by mail to your address. You collect the sample at home and send it back to the lab for testing.

The Cologuard testing kit will contain a sample container, a tube, preserving liquid, labels and instructions on how to collect the sample. When you are ready to have a bowel movement, use the Cologuard testing kit to collect your stool sample.

Read the instructions that come with the testing kit carefully. Wait until you are ready to have a bowel movement. Collect the sample only when it is possible to ship it within 24 hours. The sample must reach the lab in 72 hours (3 days).

DO NOT collect the sample if:

Follow these steps to collect the sample:

The results of the test will be sent to your provider in two weeks.

How to Prepare for the Test

The Cologuard test does not require any preparation. You do not need to change your diet or medicines before the test.

How the Test will Feel

The test requires you to have a normal bowel movement. It will not feel any different from your regular bowel movements. You can collect the sample at your home privately.

Why the Test is Performed

The test is done to screen for colon and rectal cancer and abnormal growths (polyps) in the colon or rectum.

Your provider may suggest Cologuard testing once every 3 years after age 50 years. The test is recommended if you are between ages 50 to 75 years and have an average risk of colon cancer. This means that you do not have:

Normal Results

The normal result (negative result) will indicate that:

What Abnormal Results Mean

Abnormal result (positive result) suggests that the test found some pre-cancer or cancer cells in your stool sample. However, the Cologuard test does not diagnose cancer. You will need further tests to make a diagnosis of cancer. Your provider will likely suggest a colonoscopy.


There is no risk involved in taking the sample for Cologuard test.

Screening tests carry a small risk of:


It is unclear yet whether the use of Cologuard will lead to better outcomes compared with other methods used to screen for colon and rectal cancer.

Review Date: 1/8/2019
Reviewed By: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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