On this page
- How a colonoscopy works
- How Cologuard works
- Accuracy, side by side
- What stool testing is good at
- Where stool testing falls short
- What colonoscopy is good at
- Where colonoscopy falls short
- What a positive Cologuard result means
- How to choose between them
- Cost & insurance
- Frequently asked questions
- Choose the right colon test in Fort Smith
How a colonoscopy works
A colonoscopy is an examination of the entire lining of the colon, done under sedation with a soft, flexible scope. Most exams take well under an hour, and most patients remember none of it. What sets it apart from every other screening option is that it is a test and a treatment at once: if a polyp is found, it is removed in the same appointment. Dr. Ihab Herraka performs colonoscopy in our own on-site endoscopy center in Fort Smith, alongside the rest of our procedures and testing.
How Cologuard works
Cologuard is an at-home stool test, more precisely a multi-target stool DNA test. A kit arrives at your house, you collect one bowel movement in it, and you mail it back; the lab looks for hidden blood and for altered DNA that polyps and colorectal cancers shed into stool. There is no prep, no sedation and no change to your diet or medications. It is available by prescription for average-risk adults 45 and older who have no symptoms, and it is repeated every three years. A next-generation version, Cologuard Plus, has been approved and is being phased in; it is collected the same way.
Accuracy, side by side
Accuracy depends on which version of Cologuard is being discussed, and the numbers are worth naming rather than summarizing.
- Original Cologuard, evaluated in the DeeP-C study, detected about 92% of colorectal cancers and 42% of advanced adenomas (precancerous polyps large enough to matter), with a false-positive rate of about 13%.
- Cologuard Plus, the newer version now being phased in, reports improved figures in the manufacturer's studies: about 95% cancer detection with a false-positive rate closer to 9%.
- Colonoscopy is considered more than 95% accurate for detecting cancer when the prep is adequate, and it is the only one of the three that removes a polyp rather than just reporting it. These figures describe how well each test finds a problem that is already there. They do not describe prevention, which is where colonoscopy's advantage lies: it can remove a polyp before it ever becomes the thing being screened for.
What stool testing is good at
Stool testing is a real screening option, not a consolation prize, and both the American College of Gastroenterology and the U.S. Preventive Services Task Force list it as acceptable.
- Nothing to drink and no sedation. No cleanout the night before, no IV, no driver waiting on you.
- No day away from work. It happens at home, on your own schedule.
- It detects most colorectal cancers (see the accuracy figures above), because cancers tend to bleed and shed abnormal DNA.
- It gets people screened who otherwise would not be. A stool test you complete protects you more than a colonoscopy you keep putting off.
Where stool testing falls short
- It detects; it does not prevent. A colonoscopy can remove a polyp before it becomes cancer. A stool test can only say that something needs a closer look.
- It finds cancer better than it finds the polyp that would have become one. Precancerous polyps often do not bleed and shed less DNA, so many are missed.
- The interval is three years, not ten. A kit left unopened in a closet is not screening you.
- False alarms happen, and some patients have a positive result followed by a completely normal colonoscopy.
- A positive result means a colonoscopy anyway, so for those patients the stool test added a step rather than replacing one.
- A negative result does not explain a symptom. Stool testing was built for people who feel well, and that is the only job it does. Do not use a stool test to explain something that is already wrong. Rectal bleeding, a change in bowel habits lasting more than a few weeks, unexplained weight loss and a low iron level all call for a diagnostic colonoscopy whatever a stool test said, and a negative result does not clear them. Go to the emergency department for heavy rectal bleeding, particularly with dizziness, fainting or severe abdominal pain.
What colonoscopy is good at
- It prevents cancer rather than only finding it. Most colorectal cancers begin as a polyp, and a polyp removed during the exam never gets its chance, see colon polyps.
- It looks at the whole colon directly, including flat lesions that do not bleed, and it can take biopsies. A normal exam at average risk is typically repeated in ten years.
- It is the right test when something is already wrong. Symptoms, a family history of colorectal cancer, previous polyps or inflammatory bowel disease all put you outside the group stool testing was designed for.
Where colonoscopy falls short
Being fair about it: the prep is genuinely unpleasant, and it is the part patients dread. You give up a day, you need someone to drive you home, and you cannot work or sign anything for the rest of that day. It is a medical procedure, so it carries small risks, including bleeding after a polyp is removed, a rare tear in the bowel wall, and reactions to sedation, which is why an anesthesia professional monitors you throughout. A lesion can still be missed, particularly when the prep was incomplete.
What a positive Cologuard result means
A positive Cologuard result is not a cancer diagnosis, and most people who get one do not have cancer. It means the lab found blood, altered DNA, or both, and the only test that can say where they came from is a colonoscopy. Two things follow from that. Repeating the stool test is not one of your options. A second kit cannot cancel out the first, and a reassuring repeat would not be something you could safely act on. And timing counts: the follow-up colonoscopy is usually done within a few months of the result, because long delays are linked to cancers being found at a later stage. Most often, the colonoscopy that follows a positive result turns up a polyp, which comes out during the same exam. Some exams are entirely normal. That is not a wasted trip and not a mistake. The test has a known false-alarm rate, and a clear look at the colon is a real answer. If you have a positive result in hand, call us. We start with an office visit so Dr. Herraka can go over your history and your result, and your colonoscopy is scheduled from there.
How to choose between them
For an average-risk adult with no symptoms, either test is defensible, and the better one is usually the one that actually gets done. Lean toward colonoscopy if a parent, sibling or child had colorectal cancer or advanced polyps, you have had polyps before, you have Crohn's disease or ulcerative colitis involving the colon, you have any symptoms at all, or you would rather handle this once and not think about it for a decade. Consider stool testing if you have already declined a colonoscopy and would otherwise go unscreened, if sedation carries added risk for you, or if finding a driver and a day off is the obstacle standing between you and any screening at all. Cologuard is not built for everyone, and our colon cancer screening page covers who should start before 45 and what the other accepted options are. A third option: FIT. A fecal immunochemical test (FIT) is a simpler, lower-cost stool test that checks only for hidden blood, without the DNA marker Cologuard adds. It is repeated every year rather than every three years, and for patients who want a stool-based test with a smaller price tag, FIT is a reasonable alternative to Cologuard. It shares Cologuard's main limitation: a positive result still means a colonoscopy.
Cost & insurance
A screening colonoscopy is generally covered as preventive care with no out-of-pocket cost, while one done because of a symptom or on a shorter surveillance schedule is billed under your regular medical benefits, so a deductible or coinsurance can apply. Cologuard's list price is roughly $650 (per Nebraska Medicine), though insured patients typically pay far less, or nothing, under preventive coverage. One rule changed recently, and it matters here. Medicare and most health plans now treat a colonoscopy done after a positive stool test as part of the screening process rather than as a separate diagnostic procedure. Under most commercial plans that means no cost-sharing on the follow-up exam; under Medicare the coinsurance that used to apply is being reduced in steps rather than dropped all at once. Not every plan reads the rule the same way, so ask before your date rather than after. Our insurance page lists the plans we take, Medicare and Medicaid on both sides of the state line included.
Frequently asked questions
Is Cologuard as accurate as a colonoscopy?
Not in the way most people mean by accurate. In the DeeP-C study, original Cologuard detected about 92% of colorectal cancers but only 42% of advanced adenomas, the precancerous polyps a colonoscopy would find and remove; Cologuard Plus reports improved figures near 95%/9% (detection/false-positive) in manufacturer studies. Either way, a positive result still has to be followed by a colonoscopy. It is an accepted screening test, not an equivalent one.
What should I do if my Cologuard result is positive?
Call us for an office visit, and do not repeat the stool test. We go over your history and your result first, then schedule your colonoscopy. A positive Cologuard result means blood or abnormal DNA was found in the sample, and only a colonoscopy can show where it came from. Most positive results are not cancer, a polyp that can be removed during the exam is the more common finding, and some exams turn out entirely normal. Have it done within a few months rather than letting it drift.
Who should not use Cologuard?
Cologuard is intended for average-risk adults 45 and older who have no symptoms. It is not the right test if you have rectal bleeding, a change in bowel habits, unexplained weight loss or anemia; if you have had polyps or colorectal cancer; if you have Crohn's disease or ulcerative colitis; or if a close relative had colorectal cancer or advanced polyps. Those situations call for a colonoscopy from the start.
How often do colonoscopy and Cologuard need to be repeated?
A normal screening colonoscopy in an average-risk adult is usually repeated in ten years, and sooner, often every three to seven years, if polyps were removed. Cologuard is repeated every three years, and it only counts as screening if you keep doing it on schedule.
Is Cologuard cheaper than a colonoscopy?
Not necessarily, and the sticker prices are misleading. Cologuard's list price runs roughly $650, but most plans cover a screening colonoscopy as preventive care with no out-of-pocket cost, so for many patients the cheaper-sounding option is not actually cheaper. And if a stool test comes back positive, you end up paying for both tests rather than one. Ask your plan what each is worth to you before deciding on price.
Will my insurance cover the colonoscopy after a positive stool test?
In most cases yes, and as part of screening. Medicare and most health plans now treat a colonoscopy that follows a positive stool test as a continuation of screening rather than as a new diagnostic test. Commercial plans generally apply no cost-sharing to that exam, while Medicare is phasing out the coinsurance it used to charge rather than removing it in a single step. Plans differ, so our staff verifies your benefits before your procedure date.
Choose the right colon test in Fort Smith
If you are 45 or older and have never been screened, or a stool test came back positive and you need the next step, call the Digestive & Liver Center of Arkansas Main Clinic at (479) 242-2888 or request an appointment. Dr. Ihab Herraka sees patients at 3416 Old Greenwood Rd, Fort Smith, AR 72903, Monday through Friday, 8:00 to 5:00, including patients from Poteau, Sallisaw and across eastern Oklahoma, where Oklahoma Medicaid is accepted.