Stool DNA Test

What is Stool DNA Test

A stool DNA test checks for genetic material, cell DNA, or blood in the stool. It is a screening test for cancer. Stool DNA tests, combined with other tests, are used to detect colorectal cancers, precursors of cancers, and advanced tumors. The test can be done at home instead of going to hospitals or clinics. 

Cancers or adenomas in the colon can shed abnormal or cancerous cells continuously. The DNA found in these tests is very minute. Rectal bleeding sheds red blood cells in the stools which can be detected by stool DNA tests. 

Indications

A stool DNA test is used to diagnose cancers in individuals without any symptoms. This is used as a screening test to check the changes that are invisible to the naked eye. Old cells in the colon detach from the colon and are replaced by new cells. These old cells are shed and appear in the stools. Similarly, cancer cells also shed their abnormal cells into the stool, which can be observed under the microscope. 

The stool DNA test detects these abnormal cells with abnormal genetic material or blood cells to detect cancer. It can also detect polyps which can become cancerous at any stage. This helps in the early detection of cancer or polyps that can transform into cancer. 

The stool DNA test is indicated in individuals who are 45-75 years of age. It is also indicated for individuals who are at increased colon cancer risk and have a previous cancer diagnosis in the family. These are also used to detect Inflammatory disorders of the colon like inflammatory bowel disease. 

Contraindications

A stool DNA test is not indicated in individuals with colon cancer symptoms like bleeding from the rectum, abnormal bowel habits, abdominal pain, anemias like Iron deficiency anemia, previous history of colon cancer or polyps, inflammatory bowel disease, family history of colon cancer and genetic diseases that can increase the risk of colon cancer.

Advantages

A stool DNA test has many advantages

• It helps in detection of colon cancer at early stages.
• It helps to know if polyps tend to transform into cancer. 
• It helps to identify the high-risk group of individuals. 
• It is a simple test.
• It is non-invasive.
• It is easy to use .
• No prior preparation is needed. 
• This can be done at home. 

Before the Procedure

Before undergoing the stool DNA test, one has to consult a healthcare provider and discuss the necessity and importance of the procedure. There are not many procedures to follow before doing the stool DNA test. One can take their routine medications and food. Drink water and fluids. No separate bowel preparation is necessary to empty the bowel before the test. 

About the Stool DNA Test

The stool DNA test is based on the fact that colon cancers continuously shed DNA. The shed cells can be detected in the stools. Cologuard is the U.S. FDA-approved stool D.N.A. test kit that is currently available in the market. This can detect 11 biomarkers. Biomarkers are molecules or genes that signify a specific disease by identifying the DNA in the stool, and any gene changes. This test can quantify the DNA and human hemoglobin due to the blood in the stool.  It also includes an advanced test called the fecal immunochemical test which detects abnormal genes. 

During the Procedure

One can get a stool DNA test done at home. Depending on the instructions provided by the manufacturer, one can efficiently perform the stool DNA test at home. This test has a container to collect the stool and a solution to be used as a preservative for the stool sample. 

While doing the test, open the bracket and place it on the toilet seat. Now place the container in the bracket. The bracket holds the container. One has to pass the feces into the container by making themselves sit comfortably on the toilet. After removing the container, scrape the sample kit, place it in the tube, and keep it aside. One has to add the liquid preservative to the container and close it. Now parcel it to the designated laboratory for observation. 

After the Procedure

One can resume daily living activities after a stool sample test. 

Interpretation

Stool DNA tests check for any changes in the DNA of the cells shed into the stool from the cancer and the blood in the stool to detect colon cancer. The test results are interpreted as negative or positive results. 

A negative test occurs when no abnormal DNA or blood is detected in the stools, indicating no abnormal changes occurring in the colon. In such cases, the test must be repeated after 3 years. 

A positive test is when abnormal DNA or blood is detected in the stools, indicating abnormal cancerous changes in the colon. In such cases, further investigations must be done to check for signs of cancer. 

Risks and Complications

The main associated risk with this test is false positive results where abnormal DNA or blood may be shown by the test, but it is not present in the individual. There are also chances of missing the actual presence of cancer when the individual does not have it. This is called the false-negative test. False positive tests can lead to unnecessary further investigations which can be a burden to the patients financially and psychologically. 

Conclusion

A stool DNA test is a test done using the stool of an individual to detect the presence of abnormal DNA and blood. This abnormal DNA is characteristic of colon cancers shed by the cancerous cells of the colon. This can help in the early detection of colon cancers and increase the quality of life of an individual.