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Harmony Test/NIPT

This test screens for the three most common birth defects caused by chromosomal abnormality:

  • Down Syndrome

  • Edward's Syndrome

  • Patau Syndrome

The non-Invasive Prenatal Testing (Harmony Test) is a safe, non-invasive test that measures fetal cells present in the mother's blood to produce a 99% accurate Down Syndrome screening result and fetal sex (if requested). Because the test is non-invasive it cannot harm you nor your baby.

The appointment includes an accurate dating scan and blood test with the results of the test within 7 working days.

If you have already had either the nuchal scan or integrated test and have received a high risk result you may consider this test to obtain a more accurate second opinion.

What is Non-Invasive Prenatal Testing (NIPT)?

Non-Invasive Prenatal Testing is the generic term for several different tests that are currently the most accurate screening tests available to assess whether the baby is at risk of Down’s syndrome, Edwards’ syndrome or Patau’s syndrome. The Harmony test is the NIPT we use and can be done at any time from 11 weeks of pregnancy. However, we usually recommend it is done at 12-14 weeks in conjunction with the Nuchal Translucency scan, as this scan gives us more information about how the baby is developing.

The Harmony test involves taking a sample of the mother’s blood, the lab is then able to filter out fetal cell-free DNA (cfDNA) from the maternal cfDNA and analyse this for the fetal chromosomes 21, 18 and 13 which are the cause of Down Syndrome, Edwards Syndrome and Patau’s Syndrome respectively. Likewise, the fetal sex chromosomes can be analysed to determine the sex of the baby if you wish.

What if I expect unexpected news?

As the test is a simple blood test it involves no risk to the mother or baby and has a 99% detection rate, with a very small false positive rate of 0.1%. This means the test will only miss a baby with Down Syndrome in approximately 1:70,000 pregnancies and is therefore very accurate.

However, even if the result comes back as low risk but a problem is discovered on scans later, the doctors looking after you may still discuss the possibility of chromosomal problems.

Likewise, if the test comes back as being high risk, you would be offered an invasive test called a Chorionic Villus Sample or Amniocentesis (dependent on how many weeks you are). These tests will tell you with close to 100% accuracy if the baby’s chromosomes are normal or not, but both tests involve a risk of miscarriage of 1:200., which represents a sample of a sample of the fetal-placental DNA, derived from placental trophoblasts, in the mother’s blood.

The Harmony test is a DNA test and due to the laboratory’s high-quality control (QC) standards, in approximately 3-5% of cases, the initial blood sample fails the QC testing and a result cannot be obtained. A repeat blood sample will be advised, usually a few weeks later. Even then, in approximately 1% of cases, a result still cannot be achieved from this second sample and the cost of the test would be refunded.

The accuracy of sex determination is also 99% and as this applies to all women having the test, this means it will get the sex wrong in 1:100 cases.

Can the Harmony Test be done in Twins?

The Harmony Test can be used in twin, singleton donor and surrogate pregnancies with the same level of accuracy. In a twin pregnancy if you wanted the know the fetal sex and they are monochorionic or identical twins, Harmony can confirm the sex of each twin as it will be same. For dichorionic, non-identical twins, Harmony can confirm if there are two girls, but can only confirm the presence of the Y chromosome meaning if there is a boy, they cannot confirm if you are having one or two boys. This can be looked at in other scans later.

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