The Harmony Test is a safe, non-invasive, screening test for the chance of Down Syndrome. It measures fetal DNA present in the mother's blood to produce a 99% accurate screening result. Although primarily used for Down Syndrome (Trisomy 21) it will also screen for Edward’s Syndrome (Trisomy 18), Patau’s Syndrome (Trisomy 13) and it can detect the fetal sex (if requested). It is accurate in twins as well.

The Harmony Test can be performed from 10 weeks of pregnancy in both pregnancies conceived naturally or by IVF.

The Harmony test simply involves first performing a scan to accurately date the pregnancy and look to see if it is singleton or twins. This is followed by a small blood sample and you should receive your result in under 15 days. This test does not involve any risk to the pregnancy.

The Harmony Test is very accurate for the following chromosomal conditions:

  • 99% for Down Syndrome (Trisomy 21)
  • 98% for Edwards Syndrome (Trisomy 18)
  • 80% for Patau’s Syndrome (Trisomy 13)
  • 96% Turner’s Syndrome
  • 99% for Fetal Sex

In a few cases the first blood test is inconclusive and may need to be repeated following another scan to check the pregnancy.

The Harmony test is the most accurate screening test available. However, following the result, a small number of women (Less than <1%) who have a high risk result will be offered a diagnostic test with either a Chorionic Villous Sampling (CVS) or Amniocentesis, which will give a 100% accurate result for the baby’s chromosomes but involves a small risk of miscarriage (1%).

The Harmony test does not provide information on the detailed anatomy of the baby or other physical problems such as Spina Bifida or Heat anomalies. It is therefore important that you have all the usual ultrasounds scans during the pregnancy even if the Harmony Test shows a low risk result.

If you would like to receive more information on the Harmony Test at New Victoria Hospital or to make an appointment, please call our Imaging Department on 020 8949 9030 or:

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