Several at-home options for colon cancer screening are available. If any of these tests are positive, a doctor will recommend a colonoscopy for further analysis.

The U.S. Preventive Services Task Force recommends colorectal cancer screening for adults ages 45 to 75. Screening can help find precancerous growths or cancer in the early stages. If cancer is found early, it can be easier to treat.

You can undergo certain screening tests for colon cancer at home. Others are performed by a doctor, and you must visit a hospital or clinic. Here’s a breakdown of the different options for colorectal cancer screening.

The fecal occult blood test (FOBT) is a test that you can do at home using a kit from your doctor. The test looks for blood in the stool that you can’t easily see. You place a small stool sample on a card or into a container using a stick or brush and return it to the doctor for testing.

If the test is positive, a doctor will recommend a colonoscopy. A positive test means there is microscopic blood in the stool, which can relate to several conditions, including cancer.

There are two types of FOBT. With the guaiac FOBT (gFOBT), you might have to avoid some foods like red meat before the test. With the immunochemical FOBT (or fecal immunochemical test, FIT), you won’t have to change your diet.

Doctors advise undergoing these tests every 1 to 2 years.

The multitarget stool DNA testing (sDNA-FIT) (Cologuard) is a combined test that looks for blood in the stool and genetic signs of colon cancer. You can do this test at home. You’ll need a prescription from a doctor to order a kit online.

sDNA-FIT tests a full bowel movement. The kit comes with the supplies you need to collect the sample and ship it back to the lab. You don’t have to change what you eat or make any special changes before doing the test.

If the test is positive for blood or genetic changes, a doctor will recommend a colonoscopy. The DNA stool test is recommended every 3 years.

A virtual colonoscopy uses CT images to create a detailed picture of the colon and the rectum. The images can show polyps and other changes that need medical attention. Before this test, you need to cleanse your colon using a bowel prep kit.

If a virtual colonoscopy shows polyps, you may need a regular colonoscopy to remove them. This test can also miss smaller polyps.

Doctors recommend a virtual colonoscopy every 5 years.

A doctor places a thin, flexible tube up the rectum to perform a sigmoidoscopy. They check the lower third of the colon and the rectum for polyps or other signs of cancer. The doctor can remove any polyps during the procedure and send them for testing.

Before the procedure, the lower part of the colon is emptied of stool. The bowel-cleansing prep is not as extensive as that for a colonoscopy, and you probably won’t need sedation.

A sigmoidoscopy is recommended every 5 years, or every 10 years if a person also has a yearly FIT test.

A colonoscopy involves guiding a thin tube up the entire colon. During the procedure, a doctor can examine the entire bowel and remove any polyps or growths.

Before you have a colonoscopy, you will cleanse the entire colon with a bowel prep kit. You might receive sedation for the procedure.

Doctors recommend a colonoscopy every 10 years.