Screening Tests At-a-Glance

Colorectal Cancer Screening Saves Lives

The U.S. Preventive Services Task Force (USPSTF) recommends colorectal cancer screening for men and women aged 50–75 using high-sensitivity fecal occult 

blood testing (FOBT), sigmoidoscopy, or colonoscopy. The decision to be screened after age 75 should be made on an individual basis. If you are older than 75, 

ask your doctor if you should be screened. 

The benefits and potential harms of the recommended screening methods vary. Discuss with your doctor which test is best for you. Getting screened could 

save your life!

Recommended Screening Tests for Colorectal Cancer

Name Preparation What happens? Frequency

High-Sensitivity Fecal Occult Blood Test (FOBT) or 

Stool Test; or Fecal Immunochemical Test (FIT)

Note: There are two types of FOBT: one uses 

the chemical guaiac to detect blood. 

The other—a fecal immunochemical test (FIT) 

uses antibodies to detect blood in the stool. 

Your doctor may recommend that you follow 

a special diet before taking the FOBT. 

You receive a test kit from your health care 

provider. At home, you use a stick or brush to 

obtain a small amount of stool. You may be asked 

to do this for several bowel movements in a row. 

You return the test to the doctor or a lab, where 

stool samples are checked for blood.

This test should be done every year.

(If anything unusual is found, 

your doctor will recommend a 

follow-up colonoscopy.)

Ask your doctor for a high-sensitivity FOBT or FIT. 

The one time FOBT done by the doctor in the 

doctor’s office is not appropriate as a screening 

test for colorectal cancer.

Flexible Sigmoidoscopy (Flex Sig)

Note: this is sometimes done in combination 

with High-Sensitivity FOBT.

Your doctor will tell you what foods you 

can and cannot eat before the test. 

The evening before the test, you use a 

strong laxative and/or enema to clean 

out the colon.

During the test, the doctor puts a short, thin, 

flexible, lighted tube into the rectum. This tube 

allows the doctor to check for polyps or cancer 

inside the rectum and lower third of the colon.

This test should be done every 

5 years. When it is done in 

combination with High-Sensitivity 

FOBT, the FOBT should be done 

every 3 years. 

(If anything unusual is found, 

your doctor will recommend a 

follow-up colonoscopy.)

Colonoscopy

Note: Colonoscopy also is used as a follow-up 

test if anything unusual is found during one of 

the other screening tests.

Before this test, your doctor will tell 

you what foods you can and cannot eat. 

You use a strong laxative to clean out 

the colon. Some doctors recommend that 

you also use an enema. Make sure you 

arrange for a ride home, as you will not be 

allowed to drive.

You will receive medication during this test, 

to make you more comfortable. This test is 

similar to flex sig, except the doctor uses a longer, 

thin, flexible, lighted tube to check for polyps or 

cancer inside the rectum and the entire colon. 

During the test, the doctor can find and remove 

most polyps and some cancers. 

This test should be done every 

10 years. If polyps or cancers 

are found during the test, 

you will need more frequent 

colonoscopies in the future.

For more information, please call 1-800-CDC-INFO 

(1-800-232-4636) or visit www.cdc.gov/screenforlife
Other Screening Tests At-a-Glance

Colorectal Cancer Screening Saves Lives

Other Screening Tests In Use or Being Studied

Name Who recommends it? What is involved? Important considerations

Double Contrast Barium Enema (DCBE) American Cancer Society

(recommends every 5 years.)

Before this test, you follow a special diet and use a 

strong laxative or enema to clean out the colon. 

During the test, you receive an enema with a liquid 

called barium that flows from a tube into the colon, 

followed by an air enema. The barium and air 

create an outline around your colon, allowing the 

doctor to see the outline of your colon on an X-ray. 

If anything is found during this test, 

you likely will need a colonoscopy.

Virtual Colonoscopy 

(also known as computed 

colonography or CTC)

tomographic (CT) 

American Cancer Society

(recommends every 5 years.)

You prepare for this test as you would for a 

colonoscopy. Before the test, you follow a 

special diet and use a strong laxative to clean 

out the colon. Virtual colonoscopy uses x-rays 

and computers to produce images of the 

entire colon. The images are displayed on the 

computer screen.

This test is recommended by 

at least one group that issues 

screening guidelines, but other 

groups say more studies are 

needed to measure its effectiveness 

and to better understand its benefits 

and potential harms. 

Many insurance plans do not yet 

cover this test for screening.

If anything is found during this test, 

you likely will need to have a ‘regular’ 

colonoscopy, described on the 

other side.

Stool DNA test American Cancer Society For this test you 

and send it to a 

collect an entire bowel movement 

lab to be checked for cancer cells. 

This test costs more than the other 

FOBT or stool tests. If something is 

found, you will need a colonoscopy.

It is not yet known how often this test 

should be done.

Most insurance plans do not cover 

this test.

For more information, please call 1-800-CDC-INFO 

(1-800-232-4636) or visit www.cdc.gov/screenforlife

CDC Publication #21-1029 • August 2009