Cologuard Stool Test

Why would a doctor order Cologuard?

Doctors order Cologuard for people at average risk for colon cancer who have no symptoms. Most major guidelines now recommend that average-risk adults start colon cancer screening at age 45. Cologuard is one approved way to do that screening, alongside a regular colonoscopy and simpler stool tests.

It is a good fit when:

• You are between 45 and 85 and feel healthy.
• You want to screen without the prep, sedation, and time off that a colonoscopy needs.
• You do not have symptoms like bleeding, belly pain, or a change in your bowel habits.

Cologuard is not the right test for everyone. Your doctor will likely steer you toward a colonoscopy instead if any of these are true:

• You have symptoms. Blood in your stool, ongoing belly pain, or a change in your bowel movements needs a direct look, not a screening test.
• You are at high risk. A personal history of colon cancer, large polyps, inflammatory bowel disease such as Crohn's disease or ulcerative colitis, or certain inherited syndromes all call for colonoscopy.
• A close family member had colon cancer or advanced polyps. This often means earlier and more direct screening.

If you are not sure which group you fall into, a gastroenterologist can help you decide.

How do you prepare for Cologuard?

This is the part people like most. Cologuard needs no preparation at all.

You do not have to fast. You can eat and drink normally right up to the moment you collect your sample. You do not change your diet in the days before. You do not stop any of your regular medicines or supplements. There is no laxative prep and no cleanout the way there is before a colonoscopy.

A few timing details matter:

• Collect the sample when you would normally have a bowel movement, so you are not forcing it.
• Do not start the kit if you are having active rectal bleeding, are menstruating, or have bleeding hemorrhoids. Blood from those sources can throw off the result. Wait until the bleeding stops.
• Once you collect the sample, the kit needs to reach the lab within a set window, usually about 24 hours to ship and no more than a few days total. Plan to mail it back the same day or the next morning.

That is the whole prep. No diet, no fasting, no medicine changes.

How the Cologuard test works, step by step

Cologuard comes to you as a boxed kit, so the steps happen at home on your schedule.

Step 1: Get the order. A doctor has to order Cologuard for you. That can be your primary care provider, a gastroenterologist, or in some states a telehealth visit set up through the test maker. The kit then ships to your home.

Step 2: Set up the kit. Inside the box you will find a bracket that sits on your toilet, a container that holds the whole stool sample, a small tube with liquid preservative, and a bottle of liquid you pour over the sample at the end.

Step 3: Collect the sample. You attach the bracket and the container to your toilet and have a normal bowel movement into the container. You only need one. Using the small probe in the kit, you scrape a tiny bit of stool into the preservative tube and screw it shut.

Step 4: Add the liquid and pack it up. You pour the bottle of liquid over the rest of the sample in the container, close the lid, and place everything back in the box exactly as the instructions show.

Step 5: Mail it back. The kit ships with a prepaid label. You send it to the Exact Sciences lab, often by calling for a pickup or dropping it at a carrier location the same day.

Step 6: Wait for results. The lab reads the DNA markers and the blood marker and sends the result to your doctor, usually in about two weeks. You and your provider then go over what it means.

What do your Cologuard results mean?

Cologuard gives one of two answers: negative or positive.

A negative result means the test did not find the DNA changes or hidden blood it looks for. That is reassuring. For an average-risk person, a negative result usually means you can wait three years and repeat the test, unless your doctor advises otherwise. Negative does not mean zero risk, which is why the test repeats on a schedule.

A positive result means the test found something worth a closer look. Know this above all: a positive Cologuard is not a cancer diagnosis. It is a signal. Many positive results turn out to be polyps that are easy to remove, and some turn out to be nothing harmful at all.

If your result comes back positive, do not panic, but do not delay either. Call your provider and get the colonoscopy scheduled.

How accurate is Cologuard?

Cologuard is good at catching colon cancer and weaker at catching early precancer. Both numbers matter when you choose a screening test.

In the large study the FDA reviewed, Cologuard found about 92 percent of colon cancers. That is strong. It found about 42 percent of advanced precancerous polyps, which is much lower. So the test is better at spotting cancer that already exists than at catching the large polyps you would want removed before they turn into cancer. A colonoscopy finds and removes those polyps in the same visit, which is one reason doctors still consider colonoscopy the most complete option.

Cologuard is also not perfect on the other side. Its specificity is about 87 percent, which means roughly 13 out of every 100 people without cancer or advanced polyps will still get a positive result. These are called false positives, and they lead to a colonoscopy that turns up nothing serious.

Two limits worth remembering:

• A false negative is possible. A normal Cologuard does not fully rule out a polyp or an early cancer that was not shedding enough DNA or blood that day.
• It only screens. Cologuard cannot remove a polyp, biopsy a growth, or look at your colon. It can only tell you whether you need that closer look.

Risks and safety: what Cologuard can miss

Cologuard is safe to take. You are collecting a stool sample, so there is no needle, no sedation, and no risk from the test itself. The real safety issue is what can be missed and what people do after the result.

Do not use Cologuard in place of a colonoscopy if you have symptoms. Blood you can see, belly pain, unexplained weight loss, or a clear change in your bowel habits are reasons to see a doctor for a direct exam, not to mail in a stool kit. A screening test can read normal while a real problem goes unfound.

A normal result is not a free pass. Because Cologuard misses many early precancers and some cancers, a negative result still means you screen again in three years. Treating one normal test as the end of the matter is the most common mistake.

A positive result must be followed up. The FDA approval and every guideline are clear that a positive Cologuard needs a colonoscopy. Putting it off is the part that causes harm, not the test.

Watch the red flags between tests. New rectal bleeding, ongoing belly pain, or a lasting change in your stool should send you to a provider right away, no matter what your last Cologuard showed. Trust your body over the calendar.

How much does Cologuard cost and where to get it?

Cologuard is often free, but the price depends on your coverage. The list price is around $508 to $681, and most people pay far less than that.

Under the Affordable Care Act, recommended colon cancer screening is a preventive service, so most private insurance plans cover Cologuard at no cost to you when you are at average risk and within the recommended age range. Medicare covers Cologuard once every three years for people 45 to 85 at average risk, with no out-of-pocket cost.

To get the test, you need a doctor's order. You can ask your primary care provider, see a gastroenterologist, or in many states use the telehealth path the manufacturer offers. A gastroenterologist is also the right person to talk to if you are weighing Cologuard against a colonoscopy, or if your result comes back positive and you need that follow-up scheduled.

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Cologuard is covered as preventive screening by most private plans and by Medicare for average-risk adults, so most people pay nothing. The list price applies mainly to self-pay. If a positive result leads to a follow-up colonoscopy, confirm coverage of that colonoscopy with your plan first.

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Medical disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you have a medical emergency, call 911. Our editorial standards