![]() ![]() ![]() The PPV of the test is 37% for Edward’s syndrome and 49% for Patau’s syndrome. The reported sensitivity for these is 97% (T18) and 94% (T13), meaning that for Edward’s syndrome, approximately 3% of babies who have the condition will not be detected on Harmony testing and for Patau’s 6% of babies who have the condition will not be detected with the Harmony test. This means it is less possible to be certain of test performance. Test performance for Edward’s and Patau’s SyndromesĮdward’s syndrome (trisomy 18) and Patau’s syndrome (trisomy 13) are rarer conditions. Therefore for high chance harmony test results an invasive test such as amniocentesis or chorionic villus sampling is recommended to give diagnostic results. One large study reported the PPV for low risk women to be 82% for Down’s syndrome. If you are low risk the positive predictive value will be much lower, again the risk depends on factors such as your age. If you have had a high chance result for Down’s syndrome from an NHS screening test or are in an older age group the positive predictive value will be above 90%. The PPV depends upon the background risk. This is the likelihood that a result stating a high chance that the baby has the condition, is correct. This means that the harmony test will pick up more than 99% of babies who have Down’s syndrome.īecause the sensitivity is not 100% there is a small chance (less than 1%) that a harmony test may report a low probability of the baby being affected when in fact the baby does have the condition.Īnother aspect of test performance is its “positive predictive value” (PPV). This screening test has a high “sensitivity” for Down’s syndrome (Trisomy 21) of over 99%. You can have a Harmony test at Somerset Early Scans from 10 weeks of pregnancy onwards. The test looks at DNA from the baby that is present in the mothers bloodstream. In these conditions there are 3 copies of certain chromosomes instead of 2 (“Trisomy”). The Harmony test is a blood test that looks for whether your baby has Down’s Syndrome, Edward’s or Patau’s Syndrome. 10 weeks is a great milestone.Harmony – Book Now £419 / £459 with ultrasound scan Non invasive prenatal testing I only just found out I'm pregnant again so we have some time to think about it. What I'm struggling with a little is whether, if we're going to do Harmony anyway, we should take up the medical system's time with IPS. Since my dating ultrasound was at 7 weeks the physical changes in the baby were enormous in those 6 weeks so that was really cool to see. One side benefit of the IPS is that you get an ultrasound at around 13 weeks or so. We're now mulling over whether we want to do the IPS and then Harmony if it suggests a problem or just go straight to Harmony. With my first I was 35 and we didn't do this test but did do the IPS screening, which is the genetic screening that involves 2 blood tests and an ultrasound and is separate from the 20 week scan that everyone gets. I'm 37 and pregnant with #2 and seriously considering the Harmony test. The purpose of that scan is in part to pick up markers for genetic abnormalities but also to check out the baby physically while he or she is big enough to be able to see things but not so big that the ultrasound can't capture a good image. Regardless of what kind or whether you do any prenatal genetic testing, they will send you for an anatomy scan around 20 weeks.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |