Harmony Downs Screening
The Harmony Downs Test is now available from First View Imaging and uses a blood sample to test for Down's syndrome, Edward's syndrome and Patau syndrome with previously unmatched accuracy.
What is the Harmony test?
It has been discovered that a blood sample taken from the mother at any time from early pregnancy can be analysed for cell free fetal DNA, which is essentially a marker in the mother’s blood of the DNA of the baby. The result of the simple blood test (Harmony), taken at 10 weeks or later, is predictive to more than 99% in Down’s syndrome, 98% of Edwards syndrome and 80% of Patau’s syndrome which will hugely reduce the need for invasive testing by CVS or amniocentesis. It is important that an ultrasound scan is performed just before the blood test to confirm the pregnancy, and to check that the mother is not carrying twins or more. The result of the Harmony is predictive in more than 99% in Down’s syndrome cases.
This is now one of the most accurate, non-invasive tests to predict the chance of a chromosomal abnormality in a pregnancy (greater than 99% for Down’s syndrome).
Who needs a Harmony Test?
Anyone who wants extra reassurance about the normality of the pregnancy can have the test. Women who may need it are those who are anxious about their baby having a chromosomal abnormality such as Down's syndrome, Edwards syndrome or Patau's syndrome; older women (particularly over 40 years), and; those who have already had a chromosomally abnormal pregnancy. Those who are at particular risk of miscarriage should they have an amniocentesis or chorionic villous sample also find the test very attractive as it avoids an invasive procedure. It is also considered helpful for those who have had a previous sex chromosome abnormality such as Turner's syndrome.
How is the test done?
- The mother has to read and sign a consent form and sign a form for data release.
- An ultrasound scan is always done first.
- This is a simple blood test from the vein in the woman's arm like any other blood test. There is no risk to the mother or baby from having the test.
- The tubes are immediately packaged and sent to The Doctors Laboratory in London for testing.
How long does it take to get a result?
The result is usually available within 10-14 days. There is a one in thirty chance that no DNA is obtained. This is not a positive or negative test; it is an unsuccessful test. An offer of a repeat test is made free of charge. This is usually successful.
How is the result expressed?
The result is expressed as a probability. It is a screening test and not a diagnostic test. A good test result gives a risk of a chromosomal problem of less than 1:10000. A bad result gives a risk of 1:2. A risk of 1:2 requires an amniocentesis or chorionic villous sampling depending on the clinical situation. The couple are counselled about this.
How much does it cost?
The test is currently £370 including the ultrasound scan.
What happens after the test?
Depending on how many weeks pregnant you are, you will still have the opportunity to have a 12 week scan privately or with the NHS. The focus of the 12 week scan will change as you will already have the result of the Downs syndrome test, so the 12 week scan will look at the baby in detail for structural abnormalities (these may exist without a chromosomal abnormality). You will still have the opportunity to have the later scans, such as the 20 weeks scan, as before.
Are there problems this test will not detect?
Yes. Structural abnormalities such as Spina Bifida, heart defects and a poorly growing baby will only be seen on scans and often not until later scans. These scans should still be undertaken.
This new test has been developed by Ariosa Diagnostics (www.ariosadx.com) and is quality controlled by ariosa diagnostics.