Cell free fetal DNA testing, or shortly cffDNA is a new test that gives parents’ the ability to know whether their unborn baby suffers from certain chromosome disorders. Such disorders include Down Syndrome, Patau Syndrome, and Edwards Syndrome. Besides these, any other condition connected to irregular chromosome numbers can be detected. Of course, other tests in the past existed and still exist, such as amniocentesis, which give accurate results. However, one of the most positive aspects of cffDNA is the non-invasive method of examination which is done through the mother’s blood. The material which is examined is the cffDNA. This is the genetic material that is released by the placenta into the bloodstream of the mother. The release of cffDNA starts in the initial trimester of the pregnancy. At the beginning of the pregnancy, it is released in low quantities, but it increases as the pregnancy progresses. It serves to detect the genetic map of the baby that is developing.
This test represents a screening test, rather than a diagnostic test. It is not standard in use as the older routine prenatal tests, but it can be requested. This test gives more accurate, specific and sensitive data. In cases when the screening findings appear abnormal, the direction of the procedure turns to more invasive methods such as CVS (chorionic villus sampling) and amniocentesis. Only after the latter two are performed, a correct diagnosis can be carried out.
As stated, cell free DNA testing can be ordered, but usually under certain circumstances. These may include cases when the mother has an increased possibility of carrying a child that has increased risk of a chromosome disorder because of maternal age, previous pregnancy with a trisomy, known circumstances that place the fetus at risk, as well as several other related factors.
After the test has been performed and the protein examined, the results can be positive or negative. If the cffDNA results are negative, then it means that the circumstances for the baby having a trisomy 21, 18 or 13 are highly unlikely. However, other types of chromosome abnormalities that have not been tested should not be excluded just yet. If the test results are positive then the fetus is at increased risk. As mentioned, this is only a screening test. After receiving positive results, then it is obligatory to perform the diagnostic tests to be certain.
Additional information about the DNA test
The cffDNA test is still new and being worked on, so it may take a while until it becomes routine clinical use. As the research expands, so do the possibilities of usage of the test. Some of the flaws of the test are the false negative results which a mother can get if the test was performed before the tenth week of the pregnancy. This can happen because of the scarcity of the protein in the woman’s bloodstream. Test results can also be affected by obesity, which in turn decreases the amount of the cffDNA in blood. Researchers have also found a rare instance where different cell lines with genetic information can appear in the placenta. That means that some cells can contain a trisomy, while others don’t, thus giving a false prediction about the overall pregnancy in general.
What are your thoughts on the reliability of cffDNA testing?
Computed tomography (CT) scans can help doctors to avoid missing or delaying a diagnosis of cancer or other serious medical conditions. However, the exposure to ionizing radiation that these tests involve may, at the same time, increase a patient’s risk of developing cancer.
This why many doctors and organizations are calling for patients to learn more and discuss the risks and benefits of a CT scan with their doctor before they undergo one, as ABC News/Health.com recently reported.
According to the article, CT scans have become increasingly used by doctors to check a patient for cancer due to the fact that they are cheaper and faster than MRIs or exploratory surgery and provide more detail than traditional X-rays. Between 1980 and 2013, the number of CT scans performed each year in the U.S. soared from around 3 million to 76 million, the article states.
However, a patient undergoing a CT scan generally receives a high dose of ionizing radiation. While the body can repair damage caused by small doses of radiation, the high dosage in a CT scan is one that simply overwhelms the body’s “repair mechanisms,” potentially leading to cancer, the article states.
The cancer risk is higher if a patient undergoes multiple CT scans, and women may face a higher possibility of developing cancer from the radiation than men, according to ABC News/Health.com.
The report cites a 2009 National Cancer Institute study which found that 29,000 future cases of cancer could result from 72 million CT scans that were performed in the U.S. in 2007.
Cardiologists Call for Patient-Doctor Discussion About CT Scans
As Reuters reports, several medical organizations issued a statement in September2014 in the medical journal, Circulation, which urged doctors to carefully discuss the risks and benefits of chest CT scans with their patients and to explain to patients why a CT scan was being used in their case.
Ultimately, a patient and doctor must “share” the decision to go forward with the test, according to the statement, which was signed by organizations that included the American Heart Association and American College of Cardiology.
Dr. Andrew J Einstein of Columbia University in New York told Reuters that patients should not necessarily be “scared off” by the discussion or refuse undergoing what could be a potentially life-saving test.
Still, Einstein said, “As doctors, it is our obligation to make sure that we, our colleagues and our patients understand the potential benefits of a medical imaging study as well as potential risks,” according to Reuters.
Questions You Should Ask Your Doctor
If you are suffering symptoms of cancer or any other serious medical condition, your doctor may tell you that he or she would like to order a CT scan. Before you agree to undergo the test, ask your doctor:
- What specific symptoms make the CT scan necessary?
- Could alternatives such as X-rays, MRIs or ultrasounds be used instead, and how do those alternatives compare to a CT scan in terms of risks and benefits? You may also ask about how the alternatives compare in terms of cost and the amount of time involved to perform each one.
- If a CT scan is needed, what is the typical dosage of radiation for such a scan and/or the actual dosage that will be used in this specific test?
- Will there be additional CT scans? If so, how many more tests? What are the risks and benefits of multiple CT scans?
The bottom line is that you have the right, as a patient, to have as much information as possible about the tests your doctor orders you to undergo. Ultimately, if you find that the risks outweigh the benefits, you have a right to withhold consent and seek a second medical opinion.