Cologuard is an at-home prescription stool DNA test for colorectal cancer screening. It detects specific DNA alterations and blood abnormalities in the stool that may indicate the presence of colorectal cancer or precancerous polyps.

Colorectal cancer starts in the colon or the rectum. It typically begins as small, noncancerous growths known as polyps that can develop into cancer over time.

According to the American Cancer Society (ACS), a stool DNA test, or multitargeted stool DNA test, can help to detect signs of colorectal cancer or polyps. Cologuard is the only test available in the United States that tests for both DNA changes and the presence of blood.

This article discusses how Cologuard works, who it is suitable for, and how often a person should use it. It also looks at how to use Cologuard, the results a person can expect, and where to get the test.

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Cologuard is a noninvasive stool-based screening test for colorectal cancer that works by detecting specific DNA alterations and blood abnormalities that have an association with the disease.

A 2019 article notes that Cologuard uses a multitargeted approach to analyze DNA from cells shed into the stool. It also measures the presence of hemoglobin in the stool, indicating the presence of blood.

Blood in the stool may result from bleeding in the colon or rectum, which can occur in colorectal cancer or precancerous polyps.

Cologuard has two steps: Collecting a stool sample and DNA and blood analysis.

The first step involves collecting a stool sample at home using a Cologuard collection kit. The kit contains a special container for collecting the sample.

People then send their stool sample to a laboratory for advanced testing. The laboratory analyzes the sample to detect specific DNA alterations and blood biomarkers indicative of colorectal cancer or precancerous polyps.

Cologuard is a screening test for colorectal cancer that is suitable for adults who are at average risk for the disease. Average-risk individuals are those who do not have specific risk factors that place them in a higher-risk category.

According to the ACS, those with an average risk of developing colorectal cancer should begin screening at age 45.

Screening should continue until the age of 75, although the decision to screen after that age should be individualized according to the person’s health, preferences, and life expectancy.

The company stresses that Cologuard does not replace a diagnostic colonoscopy, nor does it replace a surveillance colonoscopy in those with a high risk of developing colorectal cancer.

The ACS recommends that people screen for colorectal cancer with a stool DNA test every 3 years.

However, screening recommendations can vary depending on age, medical history, family history, and risk factors.

Therefore, it is always best for a person to consult a healthcare professional who can assess specific situations and provide personalized recommendations.

A person should perform the following steps:

  1. Empty the bladder to avoid getting too much urine in the sample.
  2. Open the kit and check the expiration date.
  3. Place the sample container in the toilet bracket.
  4. Use the kit to collect the sample, following any instructions provided.
  5. Scrape the sample and fill it with the preservative liquid.
  6. Schedule a delivery with UPS using the prepaid shipping label.

It is important to return the sample on the same day or the next day after collecting the sample.

If blood is present in the stool as a result of hemorrhoids or menstruation, a person should avoid using Cologuard. This is because it can cause a false positive result.

A person may get one of the following results:

  • Positive: If a person gets a positive result, it means the test has detected abnormal DNA or blood in the stool that could result from precancer or cancer. A person should speak with a healthcare professional if they get a positive result, as they will require a colonoscopy.
  • Negative: This means that the test did not detect abnormal DNA or blood in the stool. However, false negatives can occur. A person should still schedule regular screenings.
  • Result not obtained: This means that the test could not provide a person with a result. In this case, a person may need to provide an additional stool sample.

Cologuard is a prescription-only screening test for colorectal cancer, requiring a healthcare professional’s authorization before a person can purchase it.

To obtain Cologuard, people must consult a healthcare professional, such as a primary care physician or gastroenterologist. They will assess eligibility for the test on the basis of a person’s age, medical history, and risk factors.

It is also possible to request Cologuard online via the website. Telemedicine providers will ask a person to fill out a questionnaire or attend an online consultation or phone call.

If the healthcare professional determines that Cologuard is appropriate for the person, they will issue a prescription for the test and order it from the manufacturer, Exact Sciences.

Shipping times and fees may vary, so checking with the manufacturer for specific details is best.

Under the Affordable Care Act, private insurers and Medicare are mandated to cover the expenses in relation to colorectal cancer screening tests.

As per the law, people should not incur any out-of-pocket costs, including co-pays or deductibles, when undergoing these screening tests. The aim is to ensure that individuals can access these vital screenings without facing financial barriers.

Cologuard reports that nationwide, more than 94% of people who use Cologuard have no out-of-pocket cost for screening.

A clinical study in 2014 demonstrated that Cologuard detected about 92% of colorectal cancers and about 42% of advanced precancerous polyps. This suggests that Cologuard can be a valuable tool for detecting colorectal cancer.

Additionally, a 2019 article states that Cologuard:

  • does not require medication or diet restrictions
  • does not require bowel preparation
  • is suitable for a person to perform at home
  • is part of Medicare cover

However, there is a chance that the test can provide false positives or false negatives, or potentially miss precancerous polyps.

In-person screening methods, such as a colonoscopy, have traditionally been the gold standard for colorectal cancer screening due to their ability to visualize the colon directly and detect and remove precancerous polyps.

Some people may find stool DNA tests easier than a colonoscopy. However, they will need to do these more often.

A person can use both methods of testing for colorectal cancer together. If a person receives a positive result after performing the Cologuard test, they should speak with a healthcare professional, who may then recommend a colonoscopy.

Alternative stool tests that detect blood are available, including FIT and gFOBT.

People should take the fecal immunochemical test (FIT) annually or biennially, depending on their risk factors. Doctors consider FIT to be a reliable and cost-effective screening method.

The guaiac-based fecal occult blood test (gFOBT) is also suitable for people to take annually or biennially. However, more advanced tests such as FIT and Cologuard are replacing it due to higher sensitivity and ease of use.

Here are answers to some commonly asked questions about Cologuard.

Can Cologuard detect stage 1 cancer?

The company claims that Cologuard can detect cancer and precancers.

However, it may not detect all cases, particularly those at very early stages. It is still possible for Cologuard or other screening tests to not detect stage 1 cancer.

Cologuard does not definitively diagnose cancer. A person should consult a healthcare professional before using Cologuard to ensure that it is the best option for them.

How accurate is a stool DNA test for colon cancer?

One study demonstrated that Cologuard can find 92% of colon cancers.

However, false positives and false negatives can occur in the results of colorectal cancer screening tests. According to the Cologuard website, an older 2014 study found that 13 in 100 people without cancer received a false positive result, while 8 in 100 individuals with cancer received a false negative result.

Cologuard is a stool DNA test for colorectal cancer screening that a person can do in the comfort of their own home with a prescription.

It can be a good indicator of colorectal cancers but does have limitations. People should speak with their doctor to find out if Cologuard is right for them.