Colonoscopy has long been touted as the gold standard for colon cancer screening, recommended for all adults starting at age 50. With colon cancer expected to kill more than 49,000 Americans this year, getting a colonoscopy is currently the best way to reduce your risk.

But, says Consumer Reports’ chief medical adviser Marvin M. Lipman, M.D., many people avoid colonoscopy because it includes an unpleasant 12-hour prep that includes drinking copious amounts of laxative and many trips to the bathroom, followed by the procedure itself, which typically requires anesthesia.

Instead, consumers may want to opt for one of the three at-home colon-cancer screening tests available by prescription.

A new review published in JAMA by David Lieberman, M.D., professor of medicine and chief of gastroenterology at Oregon Health and Science University in Portland, concludes that all three home tests may be a decent first-step screener—although patients still need a colonoscopy if the kits find a worrisome result.

What’s more, all of the kits can miss polyps, including precancerous growths that a doctor can spot and remove at the time of the colonoscopy.

Here’s what you need to know about the different at-home kits. 

FIT Test

The second most commonly prescribed colon-cancer screening test in the U.S. after colonoscopies, FIT tests have been in use for about 10 years.

The FIT test requires sending a single small fecal sample to a lab, which is then tested for blood. It’s a test that should be repeated annually, unlike colonoscopy, which is typically required just once every 10 years.

“A person may have a cancer that isn’t bleeding at the time of the test,” Lieberman explains, “but that same tumor may bleed and be detected when the person is retested the following year.”

Research shows that this type of test detects cancer with 79 percent accuracy. But about five percent of tests deliver “false positive” results—which result in patients having to go for follow-up colonoscopies. 

Multitarget Stool DNA Test

This test goes by the brand name Cologuard. It requires shipping an entire bowel movement to the lab. In addition to testing for blood, Cologuard looks for DNA from cancer cells scraped from the intestinal wall by feces as it passes through.

Studies have shown that this type of test detects cancer with 92 percent accuracy. However, 14 percent of tests deliver false positive results—far higher than the FIT test.

Another concern with this test is its sheer newness. Because Cologuard only received Food and Drug Administration approval in 2014, there are no studies showing that people who choose this screening method avoid dying of colon cancer in the long-term.

Studies also have not yet established the appropriate interval between testing, though the U.S. Preventive Services Task Force (USPSTF), an independent panel of health experts that advises the government, recommends repeating the test every one or three years.

Guaiac-Based Fecal Occult Blood Test (gFOBT)

This test uses a chemical called guaiac to detect hidden blood in the stool. It requires you to take annual samples from three separate bowel movements. These samples are smeared onto test cards and mailed back to your healthcare provider.

Less accurate than either the FIT or the DNA stool test, it identifies cancer only 20 to 50 percent of the time.

There are other drawbacks, too. For example, red meat and certain other foods—horseradish, cantaloupe, and broccoli, for example—can cause false positive results if eaten within a few days of the test, according to the American Cancer Society.

Certain drugs, such as ibuprofen (Advil) and aspirin, can also lead to false positives. Meanwhile, Vitamin C—either from supplements or foods—can interact with the chemicals in the test and cause a negative result, even if blood is present.

For these reasons, “the fecal occult blood test has largely been replaced with the FIT,” Lieberman says.