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[lwptoc] Cologuard is a noninvasive and precise procedure for screening colorectal cancer. The test is recommended for a person who is 45 years of age or older and for one who is at moderate risk of developing colorectal cancer. It is a screening test that uses advanced stool DNA technology and helps to detect precancer… Read More



Cologuard is a noninvasive and precise procedure for screening colorectal cancer. The test is recommended for a person who is 45 years of age or older and for one who is at moderate risk of developing colorectal cancer. It is a screening test that uses advanced stool DNA technology and helps to detect precancer and cancer at an early stage. It is not an alternative diagnostic method of colonoscopy for a high-risk person of colorectal cancer. Only after a prescription (Rx) from a doctor, you can use it.   

Additionally, cologuard is the only FDA-approved test that uses stool DNA technology. It helps find 92% of colon cancers. Most of the colorectal cancer screening test is invasive and can be uncomfortable (like colonoscopy), cologuard test is an easy technique and pain-free.

Cologuard finds out the occult hemoglobin in stool and helps to detect colorectal neoplasia linked with DNA markers. Cologuard positive result shows a clear sign of colorectal cancer or adenoma. You need to confirm it with an additional diagnostic procedure.

What is stool DNA technology for colorectal cancer?

Stool DNA technology detects changes in the cells that line inside the colon. During a bowel movement, if there are cancerous cells, your stool picks it up along with normal cells. It is one of the latest techniques used for colon cancer screening. The cologuard stool DNA method looks for abnormal DNA and hemoglobin (red blood cells) in the stool.

What is cancer screening?

Cancer screening is an active search for a cancerous cell or malignant neoplasm in a person who does not have any suspicious symptoms but is at risk of these diseases. In some cases, such tests help to detect diseases at an early stage and helps to cure many types of cancer. Screening tests can reduce cancer mortality. The United States Preventive Services Task Force (USPSTF) is committed to screening for certain types of cancer.

What is colorectal cancer?

Colorectal cancer (colon and rectal cancer) is common cancer, with more than 140,000 new cases reported annually in the United States. It usually occurs after age 50 and affects men more than women. It is the third most common cancer in men (after prostate and lung cancers) and the second most common in women (after breast cancer).

In most cases, colorectal cancer develops from polyps- a small, benign growth in the intestinal wall, which can be visualized and removed during a colonoscopy. People at risk of developing colorectal cancer and those with traces of blood in their stools should undergo a colonoscopy to detect and remove potentially cancerous polyps.

How does cologuard work?

Cologuard makes it easy to collect a stool sample in your bathroom with complete privacy. You do not need to change the routine of your medicines or follow any specific diet before the collection. Once a stool sample is collected, you need to send it to the laboratory within the next three days. Further, it will test your stool sample to identify abnormal DNA and blood traces using advanced stool DNA technology.

Who is cologuard for?

The doctor recommends a cologuard colon cancer screening test to a person who is at moderate risk of cancer (especially for people age 45+). Although it is a noninvasive method performed before colonoscopy, the cologuard test is not for everyone in case of a high risk of cancer. The doctor will not prescribe the test for the following factors:

  • A person with a prolonged history of colorectal cancer and adenomas
  • Family history of colorectal cancer 
  • Cancerous cells were detected or diagnosed positive in other cancer screening tests like colonoscopy in the last six months.
  • If you are diagnosed with symptoms or conditions such as:  
  • Inflammatory Bowel Disease (IBD)
  • Chronic ulcerative colitis (CUC)
  • Crohn’s disease
  • Familial adenomatous polyposis (FAP)
  • If diagnosed with hereditary cancer syndromes like:
  • Lynch syndrome ( hereditary nonpolyposis colorectal cancer)
  • Peutz-Jeghers Syndrome 
  • MUTYH-associated polyposis
  • Gardner’s syndrome
  • Turcot syndrome
  • Cowden’s syndrome
  • Juvenile polyposis syndrome
  • Cronkhite-Canada syndrome
  • Neurofibromatosis (NF)

How to get cologuard?

It is a compulsion for you to take a prescription from your health care provider for a cologuard test. Cologuard kits are not available directly at any medical store. On the doctor’s advice, you need to request the cologuard order requisition form from the Exact Sciences Laboratories website ( to make it easy for your healthcare provider to order the Cologuard test. Once you get the form, complete the patient demographics, insurance/billing information sections. You will get the cologuard kit to your mailing address. Store the collection kit at room temperature, without exposure to sunlight, and away from children.

How effective is the cologuard test?  

The only noninvasive FDA approved stool DNA technique finds 92% of colorectal cancer and 42% of precancers. It effectively finds a precancerous condition and cancer cells. In a clinical study on a large number of patients, compared with a fecal occult blood test, the cologuard successfully detected more precancer and cancer.

The clinical study had around 10,000 patients at 90 different locations in the United States and Canada. The age group included in the study was between 50-84. During the trial, all patients needed to undergo a fecal immunochemical test along with a cologuard test. The main aim of the study was to understand how effectively cologuard detects cancer. 

Cologuard does not guarantee an accurate result. Sometimes it produces false positive or negative results. That is why your doctor may recommend a colonoscopy.

Advantages and disadvantages of cologuard test

The Cologuard test has some result-driven advantages like:

  • You can collect a stool sample at home with the help of a kit.
  • It is pain-free. Colorguard test is a non-invasive process, that is no introduction of medical instruments into the body like it happens with colonoscopy.
  • The screening test does not require any pre-preparation or special diet to follow.

Cologuard disadvantages include:-

  • The accuracy of the cologuard test is doubtful, for which you need a follow-up test. Sometimes it shows a false result and triggers stress and fear. 
  • The false result mostly occurs for large polyps.

Risk and precautions for cologuard test

  • Do not provide a stool sample for the cologuard test if you have diarrhea and blood in the urine or stool. Avoid collecting samples if you have bleeding hemorrhoids, cuts, or wounds on your hands, rectal bleeding, menstruation. It can show a false positive and or negative result.
  • It is necessary to carry the cologuard test carefully in older patients (over the age of 75) as the possibilities of false-positive results increase.
  • Cologuard test negative results do not always indicate an absence of cancerous cells or advanced adenoma. It is highly advisable to undergo other screening methods such as colonoscopy to confirm the disease. 
  • Cologuard sometimes produces false-negative or false-positive results. If the cologuard test shows a positive result even if the colonoscopy exam does not detect any abnormal cells, then it is a false-positive result. A false negative result occurs when the cologuard fails to identify cancerous cells even if colonoscopy detects colorectal cancer. 
  • For accurate results, it is necessary to ensure the quality of the stool sample. Once collected, you need to deliver it to a laboratory within 72 hours. Follow the instructions mentioned in the cologuard patient guide for the same.
  • The risk of collecting samples with a cologuard collection kit is minimal if you strictly follow instructions provided in the patient’s guide.

What cologuard test results indicate?

  • Cologuard test positive result:

If the cologuard test comes positive, it means there are abnormal DNA cells and blood in the stool that can be a sign of precancer or cancer. If there is a suspicion positive result (false positive), the doctor will recommend you a colonoscopy to confirm the condition.

  • Cologuard test negative result:

Cologuard negative result indicates no abnormal DNA and blood detected in the stool sample. It does not guarantee the absence of precancer or cancer due to the possibility of a false-negative result. Therefore, the doctor recommends an alternate screening method.

Colorectal cancer is preventable if diagnosed in an early stage. Cologuard is one of the primary tests prescribed by the doctor, along with the immunochemical fecal test. Colonoscopy is an invasive method used to confirm the disease.