The cell-free fetal DNA test is a relatively new test that may be used to assess the risk of a pregnant woman's developing baby having a chromosome disorder, such as Down syndrome, Edwards syndrome, or Patau syndrome.
It may be used to identify other rare conditions resulting from an extra chromosome or missing piece of chromosome.
Cell-free fetal DNA is genetic material that is released by the placenta and circulates in a woman's blood during pregnancy.
It is present in small quantities starting in the first trimester and increases throughout pregnancy.
CffDNA generally reflects the genetic makeup of the developing baby.
Sean P. Kenney, MD, with the Center for Maternal & Fetal Care at Bryan Health, is here to help you better understand this procedure and how it can help determine health risks to an unborn child.
Selected Podcast
Cell Free DNA: A New Non-Invasive Test for Downs Syndrome
Featured Speaker:
Sean Kenney, MD, Center for Maternal & Fetal Care, part of Bryan Physician Network
Dr. Sean Kenney is a maternal fetal medicine specialist with the Center for Maternal & Fetal Care. Transcription:
Cell Free DNA: A New Non-Invasive Test for Downs Syndrome
Melanie Cole (Host): A test that can analyze fetal DNA called “cell free fetal DNA” is a test that can identify pregnant women who are at higher risk of having a baby with certain genetic and chromosomal conditions such as Down syndrome. My guest today is Dr. Sean Kenney with The Center for Maternal and Fetal Care, part of Bryan Physician Network. Welcome to the show, Dr. Kenney. What screenings are currently being offered for women during pregnancy?
Dr. Sean Kenney (Guest): Thank you for having me. Currently, there are diagnostic tests and screening tests. A diagnostic test would be like a coreonic villa sampling or an amniocentesis. Both of these are direct tests on the DNA of the baby but do carry a risk of miscarriage. Screening tests like first trimester screening which is a combination of biochemical hormone test and ultrasound versus a second trimester test, like a quad screen, those are just screening tests that give you a relative risk.
Melanie: Women of what age and risk factors look to have a screening test in the first place?
Dr. Kenney: All women are screened. We consider people higher risk if their above age 35 but it’s important to know that the risk only mildly increases as people have advancing gestational age. Again, someone who is over age 35 is probably a better candidate for a cell free DNA test. If someone’s less than 35 then they should have a traditional screening test which would be either the first trimester screening or the second trimester biochemical screening.
Melanie: So, tell us Dr. Kenney how does cell free DNA testing differ from the current screening tests?
Dr. Kenney: In the previous testing that we had available, we’re really looking at hormones and children with Down syndrome. We noted that some of their hormones were higher and some of their hormones were lower. So, based on the pregnancy, if they were in those ranges, we would say they were at higher or lower risk for Down syndrome. Those tests were only about 80-90% accurate and had a false positive rate of 5%, basically. So, 5% of the people that took those tests came back abnormal; whereas, with cell free DNA, the test is about 98-99% accurate and the false positive rate is only .5%. We don’t tend to scare as many people with inaccurate results.
Melanie: What’s involved in the test?
Dr. Kenney: Basically, for cell free DNA, we just send the patient to the lab with a kit and they draw the lab and send it to the company that people choose to use and get the results back, depending on the lab, anywhere from 3-12 days.
Melanie: In that three-12 days, what is it that you’re looking for? What abnormalities might a woman be told about?
Dr. Kenney: Although there are other things that can be tested for more specifically, for the most part, we’re really looking for trisomy 13, 18 and then trisomy 21, which would be Down syndrome and they can also find out the sex of the baby as well as some sex chromosome abnormalities like Turner syndrome.
Melanie: Does insurance cover this cell free DNA test?
Dr. Kenney: Most insurance companies are covering to some extent with respect to high risk patients. Some insurance companies are covering even low risk patients. If someone has a positive first trimester screen or second trimester screen or is above 35, they would be considered high risk and should be covered but, obviously, it’s important to note that you should probably find out from your insurance company if it’s covered as well. Some people also have a large deductible. So, if they have a $5,000 deductible, this is a very expensive test and it could all go to deductible.
Melanie: The patient is charged for the test and it’s up to their insurance company how much that they are charged?
Dr. Kenney: The patient will eventually get billed for the test but traditionally they work with the insurance company first and then bill the remainder.
Melanie: What happens after the test? What do you do with the results?
Dr. Kenney: Obviously, if the tests are normal and reassuring, we usually just call the patient up as well as send the results to their referring physician telling them that they had a normal test and everything looks reassuring. It’s not a 100% guarantee but it’s a pretty good test. If the test was positive, then we’d usually bring them into the office and counsel them further regarding the options. It’s important to note that this is not a 100% accurate test and that there are false positives like we talked about. Therefore, just because we have a positive test does not guarantee the baby has Down syndrome. Further testing would be offered or recommended if they were going to alter the management of the remainder of the pregnancy.
Melanie: What do you tell women about what to do with those results?
Dr. Kenney: Well, for a lot of women, if they find out that it’s likely that their baby has Down syndrome, their going to get in touch with the Down syndrome support group and kind of start making plans on what’s going to be different just so they really don’t have to worry about it. Otherwise, we just really want to sit down with the patient and decide what’s going to be best for the mom and the baby with respect to these results.
Melanie: Then, you mentioned that further testing would be recommended if she’s told that the test is positive. What is the next step in the testing line?
Dr. Kenney: Although cell free DNA can be done as early as nine to 12 weeks, usually by the time we get the results back and counsel a patient, we’d probably be looking at more like doing an amniocentesis after 14 weeks to diagnosis or exclude the chromosome abnormality that’s identified. Obviously, trisomy 21 or Down syndrome is more common. We talk about that but these tests could show other chromosome abnormalities like trisomy 13 or 18.
Melanie: Are there risks associated with amniocentesis?
Dr. Kenney: Yes. If we do an amniocentesis, there’s about a one in 200 chance of causing a miscarriage. Several women are very comfortable that they don’t want to run a risk of a miscarriage so they’ll just say we’ll evaluate the baby after the pregnancy is over with.
Melanie: Give your best advice, Dr. Kenney, for women who are newly pregnant who may or may not be at high risk. What do you tell them every day?
Dr. Kenney: I think it’s important to know what you’re value system is and what you believe. There are several people that don’t really care. They’re not going to change what happens with the pregnancy if it is Down syndrome. Some women are very worried, “Oh, my gosh I’m 35” which, statistically, only has a one in 270 chance of having a child with Down syndrome but they tend to focus on it and worry about it. A test like this, when it’s normal, is very reassuring that they just don’t have to worry about that anymore even if they weren’t going to change the pregnancy anyway.
Melanie: Tell us about your team about the Maternal and Fetal Care part of Bryan Physician Network.
Dr. Kenney: There’s myself and Dr. Byers, who’s another maternal fetal medicine specialist and we see people. We have four ultrasound techs and so, especially if the test is abnormal or for dating the pregnancy, we’ll do this comprehensive ultrasound looking for cardiac defects and other problems.
Melanie: Thank you so much for being with us today, Dr. Kenney. You’re listening to Bryan Health Radio. For more information you can go to bryanhealth.org. That’s bryanhealth.org. This is Melanie Cole. Thanks so much for listening.
Cell Free DNA: A New Non-Invasive Test for Downs Syndrome
Melanie Cole (Host): A test that can analyze fetal DNA called “cell free fetal DNA” is a test that can identify pregnant women who are at higher risk of having a baby with certain genetic and chromosomal conditions such as Down syndrome. My guest today is Dr. Sean Kenney with The Center for Maternal and Fetal Care, part of Bryan Physician Network. Welcome to the show, Dr. Kenney. What screenings are currently being offered for women during pregnancy?
Dr. Sean Kenney (Guest): Thank you for having me. Currently, there are diagnostic tests and screening tests. A diagnostic test would be like a coreonic villa sampling or an amniocentesis. Both of these are direct tests on the DNA of the baby but do carry a risk of miscarriage. Screening tests like first trimester screening which is a combination of biochemical hormone test and ultrasound versus a second trimester test, like a quad screen, those are just screening tests that give you a relative risk.
Melanie: Women of what age and risk factors look to have a screening test in the first place?
Dr. Kenney: All women are screened. We consider people higher risk if their above age 35 but it’s important to know that the risk only mildly increases as people have advancing gestational age. Again, someone who is over age 35 is probably a better candidate for a cell free DNA test. If someone’s less than 35 then they should have a traditional screening test which would be either the first trimester screening or the second trimester biochemical screening.
Melanie: So, tell us Dr. Kenney how does cell free DNA testing differ from the current screening tests?
Dr. Kenney: In the previous testing that we had available, we’re really looking at hormones and children with Down syndrome. We noted that some of their hormones were higher and some of their hormones were lower. So, based on the pregnancy, if they were in those ranges, we would say they were at higher or lower risk for Down syndrome. Those tests were only about 80-90% accurate and had a false positive rate of 5%, basically. So, 5% of the people that took those tests came back abnormal; whereas, with cell free DNA, the test is about 98-99% accurate and the false positive rate is only .5%. We don’t tend to scare as many people with inaccurate results.
Melanie: What’s involved in the test?
Dr. Kenney: Basically, for cell free DNA, we just send the patient to the lab with a kit and they draw the lab and send it to the company that people choose to use and get the results back, depending on the lab, anywhere from 3-12 days.
Melanie: In that three-12 days, what is it that you’re looking for? What abnormalities might a woman be told about?
Dr. Kenney: Although there are other things that can be tested for more specifically, for the most part, we’re really looking for trisomy 13, 18 and then trisomy 21, which would be Down syndrome and they can also find out the sex of the baby as well as some sex chromosome abnormalities like Turner syndrome.
Melanie: Does insurance cover this cell free DNA test?
Dr. Kenney: Most insurance companies are covering to some extent with respect to high risk patients. Some insurance companies are covering even low risk patients. If someone has a positive first trimester screen or second trimester screen or is above 35, they would be considered high risk and should be covered but, obviously, it’s important to note that you should probably find out from your insurance company if it’s covered as well. Some people also have a large deductible. So, if they have a $5,000 deductible, this is a very expensive test and it could all go to deductible.
Melanie: The patient is charged for the test and it’s up to their insurance company how much that they are charged?
Dr. Kenney: The patient will eventually get billed for the test but traditionally they work with the insurance company first and then bill the remainder.
Melanie: What happens after the test? What do you do with the results?
Dr. Kenney: Obviously, if the tests are normal and reassuring, we usually just call the patient up as well as send the results to their referring physician telling them that they had a normal test and everything looks reassuring. It’s not a 100% guarantee but it’s a pretty good test. If the test was positive, then we’d usually bring them into the office and counsel them further regarding the options. It’s important to note that this is not a 100% accurate test and that there are false positives like we talked about. Therefore, just because we have a positive test does not guarantee the baby has Down syndrome. Further testing would be offered or recommended if they were going to alter the management of the remainder of the pregnancy.
Melanie: What do you tell women about what to do with those results?
Dr. Kenney: Well, for a lot of women, if they find out that it’s likely that their baby has Down syndrome, their going to get in touch with the Down syndrome support group and kind of start making plans on what’s going to be different just so they really don’t have to worry about it. Otherwise, we just really want to sit down with the patient and decide what’s going to be best for the mom and the baby with respect to these results.
Melanie: Then, you mentioned that further testing would be recommended if she’s told that the test is positive. What is the next step in the testing line?
Dr. Kenney: Although cell free DNA can be done as early as nine to 12 weeks, usually by the time we get the results back and counsel a patient, we’d probably be looking at more like doing an amniocentesis after 14 weeks to diagnosis or exclude the chromosome abnormality that’s identified. Obviously, trisomy 21 or Down syndrome is more common. We talk about that but these tests could show other chromosome abnormalities like trisomy 13 or 18.
Melanie: Are there risks associated with amniocentesis?
Dr. Kenney: Yes. If we do an amniocentesis, there’s about a one in 200 chance of causing a miscarriage. Several women are very comfortable that they don’t want to run a risk of a miscarriage so they’ll just say we’ll evaluate the baby after the pregnancy is over with.
Melanie: Give your best advice, Dr. Kenney, for women who are newly pregnant who may or may not be at high risk. What do you tell them every day?
Dr. Kenney: I think it’s important to know what you’re value system is and what you believe. There are several people that don’t really care. They’re not going to change what happens with the pregnancy if it is Down syndrome. Some women are very worried, “Oh, my gosh I’m 35” which, statistically, only has a one in 270 chance of having a child with Down syndrome but they tend to focus on it and worry about it. A test like this, when it’s normal, is very reassuring that they just don’t have to worry about that anymore even if they weren’t going to change the pregnancy anyway.
Melanie: Tell us about your team about the Maternal and Fetal Care part of Bryan Physician Network.
Dr. Kenney: There’s myself and Dr. Byers, who’s another maternal fetal medicine specialist and we see people. We have four ultrasound techs and so, especially if the test is abnormal or for dating the pregnancy, we’ll do this comprehensive ultrasound looking for cardiac defects and other problems.
Melanie: Thank you so much for being with us today, Dr. Kenney. You’re listening to Bryan Health Radio. For more information you can go to bryanhealth.org. That’s bryanhealth.org. This is Melanie Cole. Thanks so much for listening.