Non Invasive Down Syndrome Screening Test
The Harmony Test
This is a simple Non invasive blood test that allows the measurement of fetal DNA in the mother's blood and can be used to detect the three most common chromosomal birth defects. The test is simple safe and accurate having a high detection rate for:
- Down Syndrome - 99%
- Edwards Syndrome - 98%
- Patau Syndrome - 80%
This test can be undertaken from 10 weeks gestation and involves a blood test from the mother and can be used instead of the Nuchal, the integrated and Quadruple test which all have accuracy rates below the Harmony Test.
Harmony Test can be undertaken if you have missed your combined test or if you have had a positive result and would like a more accurate second opinion before you make up your mind to undertake an invasive procedure with the associated risk of miscarriage (1%).
What is Tested ?
DNA from the fetus circulates in the mother's blood. Cell-free DNA (cfDNA) results from the natural breakdown of fetal cells (presumed to be mostly placental) and clears from the maternal system soon after giving birth. During a pregnancy, cfDNA can be tested to give the most accurate screening for the risk of a fetus having a common chromosome conditions.
No Risk to mother or baby.
The testing is non-invasive: it involves taking a blood sample from the mother and sent to a laboratory in London ( TDL ). The pregnancy is not put at risk of miscarriage, or from other adverse outcomes that are associated with invasive testing procedures such as amniocentesis.
High Risk Results
It is important to note that if the test results show there is a HIGH risk that the fetus has trisomy 21, 18 or 13, it does not mean that the fetus definitely has one of these conditions, although it is highly likely. For this reason, in the event of a 'high risk' (or positive) result, follow-up testing by an invasive procedure, CVS or Amniocentesis is recommended. These procedures have a 1% risk of miscarriage.
In the same way if the test results show that there is a 'LOW RISK' that the fetus has trisomy 21, 18 or 13, it is unlikely that the fetus has one of these conditions. However there is a very small risk that not all trisomy fetuses will be detected. Patients should continue with their usual scan appointments following testing.
Who can have the test?
The test is suitable for any woman who has had an ultrasound scan to confirm that her pregnancy is singleton, that the fetus is alive, and that the fetal length is equivalent to a gestation of 10 weeks or more.
We will send your blood sample along with some personal information (including name, date of birth, gestational age) to The Doctors Laboratory based in London, UK. TDL will perform the ( NIPT) test called Harmony™ Prenatal Test on the DNA extracted from your blood sample. There will be no further clinical testing on this blood and your blood sample will be discarded once we have confirmed the results with you. TDL will not use your blood sample or the extracted DNA samples for any other purpose.
In 3 to 5 % cases, a second blood sample may be necessary due to insufficient cfDNA. This will be processed by the laboratory at no extra cost.
The Result is normally available one week after the sample arrives at the Laboratory in London.
Your results will normally be sent direct to you. We will make arrangements for you to see the Fetal Medicine Consultant for a follow up appointment and discuss result in the unlikely event of the test result being in the high risk category.