What is Stool DNA Test? Purpose, Levels/Procedure & Results

A stool DNA test is a simple screening tool that looks for genetic changes and blood traces in your stool sample that might signal colorectal cancer or precancerous growths. You can collect the sample at home using a special kit, making it a convenient alternative to more invasive screening methods like colonoscopy.

This test works by detecting abnormal DNA patterns that cancer cells and large polyps shed into your stool. The most common version is called Cologuard, which combines DNA testing with a test for hidden blood to give doctors a clearer picture of your colon health.

What is stool DNA test?

A stool DNA test examines your bowel movement for microscopic traces of genetic material that shouldn't be there. When cells in your colon become cancerous or develop into large polyps, they release abnormal DNA and sometimes small amounts of blood into your digestive tract.

The test captures these warning signs before you might notice any symptoms. It's designed specifically for people at average risk of colorectal cancer, typically those aged 45 and older with no family history or personal symptoms.

Think of it as a molecular detective that can spot trouble brewing in your colon. The test looks for specific genetic mutations commonly found in colorectal cancers, plus it checks for hemoglobin, which indicates bleeding that your eyes can't see.

Why is stool DNA test done?

Your doctor might recommend this test as part of routine colorectal cancer screening, especially if you're reluctant to undergo a colonoscopy. It serves as an effective middle ground between simple blood-in-stool tests and more invasive procedures.

The main goal is catching colorectal cancer early when it's most treatable, or finding large polyps before they become cancerous. Studies show that when colorectal cancer is detected early, the five-year survival rate exceeds 90 percent.

This screening becomes particularly valuable if you have concerns about colonoscopy preparation, sedation, or time off work. It allows you to take charge of your health screening from the comfort of your home while still getting reliable results.

What is the procedure for stool DNA test?

The procedure starts when your doctor orders the test and a collection kit arrives at your home. You'll receive detailed instructions, collection containers, and prepaid shipping materials to send your sample to the laboratory.

Here's what you can expect during the collection process:

1. Collect a complete bowel movement in the provided container
2. Use the special probe to gather samples from different areas of the stool
3. Place the sample in the preservative solution included in the kit
4. Seal everything according to the instructions
5. Ship the sample back to the lab within the specified timeframe

The entire process takes just a few minutes of your time. Most people find it straightforward and much less stressful than preparing for other screening tests.

Laboratory technicians will analyze your sample using advanced DNA sequencing technology. Results typically arrive within one to two weeks after the lab receives your sample.

How to prepare for your stool DNA test?

Preparation for this test is refreshingly simple compared to other colorectal screening methods. You don't need to follow special diets, stop medications, or change your eating habits before collecting your sample.

However, timing matters for the most accurate results. Collect your sample from a naturally occurring bowel movement rather than using laxatives or enemas, which could interfere with the test's accuracy.

Make sure you have a clean, dry container to catch your stool sample. Many people find it helpful to place plastic wrap over the toilet bowl or use a disposable container to make collection easier.

Avoid collecting samples during menstruation, as blood from that source could affect results. If you're experiencing diarrhea or have been taking antibiotics recently, discuss timing with your healthcare provider.

How to read your stool DNA test?

Your stool DNA test results come back as either positive or negative, making them relatively straightforward to understand. A negative result means the test didn't find concerning levels of abnormal DNA or blood in your sample.

A positive result indicates the test detected genetic changes or blood that warrant further investigation. This doesn't automatically mean you have cancer, but it does mean you need additional testing, typically a colonoscopy, to determine what's causing these findings.

The test has a detection rate of about 92% for colorectal cancers and around 69% for large polyps that could become cancerous. However, it can sometimes produce false positives, meaning it detects abnormalities that turn out to be harmless.

Your doctor will explain your specific results and discuss next steps based on your individual situation. They'll also consider your symptoms, family history, and overall health when interpreting your results.

How to fix your stool DNA test level?

You can't actually "fix" a stool DNA test result because it's a screening tool rather than a measurement of something you can directly control. However, you can take steps to support your overall colon health and reduce your risk of colorectal cancer.

If your test comes back positive, the most important step is following through with additional testing your doctor recommends. This usually means scheduling a colonoscopy to get a direct look at your colon and determine what's causing the abnormal findings.

For long-term colon health, consider these lifestyle approaches that may help reduce your risk:

• Eat plenty of fiber-rich foods like fruits, vegetables, and whole grains
• Limit processed meats and red meat consumption
• Exercise regularly to keep your digestive system healthy
• Avoid smoking and limit alcohol consumption
• Maintain a healthy weight

These habits support overall digestive health and may help prevent the development of polyps and colorectal cancer. However, they can't change a test result that's already been processed.

What is the best stool DNA test level?

The stool DNA test doesn't measure levels in the traditional sense, so there isn't a "best" level to aim for. Instead, the test looks for the presence or absence of specific genetic markers and blood traces that suggest potential problems.

The ideal result is a negative test, meaning no concerning DNA changes or blood were detected in your sample. This suggests your colon is healthy and you can continue with routine screening according to your doctor's recommendations.

A negative result typically means you can wait three years before your next stool DNA test, assuming you remain at average risk. This timeline is longer than annual blood-based tests but shorter than colonoscopy screening intervals.

Keep in mind that even a negative result doesn't guarantee you'll never develop colorectal cancer. Regular screening remains important because the test has a small chance of missing some cancers or polyps, particularly smaller ones.

What are the risk factors for abnormal stool DNA test?

Several factors can increase your likelihood of having an abnormal stool DNA test result. Age is the most significant risk factor, with most colorectal cancers occurring in people over 50, though guidelines now recommend screening starting at 45.

Your family history plays a crucial role in your risk profile. Having a parent, sibling, or child with colorectal cancer increases your chances of developing the disease yourself, potentially leading to positive test results.

Here are the main risk factors that could contribute to abnormal results:

• Personal history of colorectal polyps or inflammatory bowel disease
• Genetic syndromes like Lynch syndrome or familial adenomatous polyposis
• Diet high in processed meats and low in fiber
• Smoking and excessive alcohol consumption
• Obesity and sedentary lifestyle
• Type 2 diabetes

Understanding these risk factors helps you and your doctor determine appropriate screening schedules and interpret results in context. However, colorectal cancer can develop in people without any risk factors, which is why routine screening remains important for everyone.

Is it better to have high or low stool DNA test result?

This question reflects a common misunderstanding about how stool DNA tests work. Unlike blood tests that measure levels of substances in your body, stool DNA tests provide a positive or negative result based on whether they detect specific genetic markers and blood traces.

A negative result is definitely what you want to receive. This means the test didn't find concerning levels of abnormal DNA or hidden blood in your sample, suggesting your colon appears healthy at the time of testing.

A positive result isn't necessarily "high" or "low" but rather indicates the test detected genetic changes or blood that require further investigation. The test doesn't provide a numerical score or level that can be compared to a normal range.

Think of it like a smoke detector in your home. It doesn't measure different levels of smoke, it simply alerts you when there's enough smoke to warrant attention. Similarly, the stool DNA test alerts your doctor when there are enough concerning findings to recommend additional testing.

What are the possible complications of abnormal stool DNA test?

An abnormal stool DNA test result itself doesn't cause physical complications, but it can create emotional stress and anxiety while you wait for follow-up testing. Many people worry immediately about having cancer, even though positive results often have benign explanations.

The main concern with a positive result is what it might indicate rather than the test result itself. If the test detected early-stage colorectal cancer or large polyps, the underlying condition requires prompt treatment to prevent progression.

However, false positive results can lead to unnecessary anxiety and additional testing. Studies show that about 13% of positive stool DNA tests turn out to be false positives, meaning follow-up colonoscopy reveals no cancer or significant polyps.

Rare complications can arise from the follow-up procedures rather than the stool test itself. If your positive result leads to colonoscopy, that procedure carries small risks of bleeding, perforation, or adverse reactions to sedation, though serious complications occur in fewer than 1 in 1,000 cases.

What are the possible complications of negative stool DNA test?

A negative stool DNA test result is generally reassuring, but it's important to understand that no screening test is 100% perfect. The main concern with negative results is the possibility of false negatives, where the test misses existing cancer or polyps.

Studies indicate that stool DNA tests may miss about 8% of colorectal cancers and approximately 31% of large polyps. This means some people with negative results might still have conditions that need attention.

The risk of false negatives tends to be higher for smaller polyps and very early-stage cancers. These conditions might not shed enough abnormal DNA or blood to trigger a positive result, potentially delaying diagnosis.

Another potential issue is that negative results might give some people a false sense of security, leading them to ignore symptoms or skip future screening appointments. Even with a negative test, you should still contact your doctor if you develop concerning symptoms like persistent changes in bowel habits, blood in stool, or unexplained weight loss.

When should I see a doctor for stool DNA test?

You should contact your doctor immediately if you receive a positive stool DNA test result. They'll help you understand what the result means and arrange appropriate follow-up testing, typically a colonoscopy, to determine the cause of the abnormal findings.

Don't wait or try to interpret the results on your own. Time can be crucial if the test detected early cancer or large polyps, and prompt follow-up gives you the best chance for successful treatment if needed.

Even with a negative result, you should see your doctor if you develop any concerning symptoms. These warning signs warrant immediate medical attention regardless of your recent test results:

• Blood in your stool or black, tarry stools
• Persistent changes in bowel habits lasting more than a few weeks
• Unexplained weight loss
• Persistent abdominal pain or cramping
• Feeling like you can't completely empty your bowels

Additionally, schedule regular check-ups to discuss your ongoing screening schedule. Your doctor will help determine when you need your next stool DNA test or whether other screening methods might be more appropriate based on your individual risk factors.