Updated 04 November 2013

Free DNA testing for Down syndrome

The Foetal Assessment Clinic in Cape Town has become the first pre-natal clinic in South Africa to offer cell-free DNA testing for Down syndrome, using only the mother’s blood.

 Clinical trial results of the Harmony Prenatal test were published in the United Kingdom last month, to great interest from medical professionals and the media due to the test’s 99.5% detection rate – the best screening result in the past 40 years of obstetric medicine.

“The existing diagnostic tests on offer – chorionic villus sampling, which involves testing a small sample of the placenta, or an amniocentesis which tests the amniotic fluid around the baby – both carry a risk that they may cause a miscarriage,” said The Foetal Assessment Centre’s co-director Dr Shannon Morris.

Non-invasive blood test

The Harmony Prenatal test offers simplicity with a non-invasive blood test performed as early as 10 weeks in pregnancy that poses NO risk to mother or foetus with a highly accurate detection of Down syndrome.

 “Our current screening tests such as serum blood tests and ultrasound are also non-invasive, but have false positive rates of up to 5%”, Morris said. “Previously, one in 20 women would be given a false positive result, but with the Harmony Prenatal test this drops to one in 1 000, so the need for invasive testing is significantly reduced”

The Harmony Prenatal test assesses the risk for chromosome conditions such as Down syndrome and includes an optional analysis of foetal sex and sex chromosome conditions. The test can be used on singleton babies, twins, IVF pregnancies and donor ova.

Morris and fellow co-director of The Foetal Assessment Centre, Dr Karin Norman, decided to bring the test to South Africa after seeing clinical evidence from the renowned Harris Birthright Research Centre for Foetal Medicine in London.

The Foetal Assessment Centre, located in Claremont and founded in 2000, has been using the test since early July, and the first batch of results were successfully received from the Ariosa Diagnostics laboratory in California 9 days later.   “This gives a turnaround time of about 10 to 12 days, so we have the results before the 12 week NT scan which is excellent.”

“Ariosa has years of experience in cell-free DNA analysis which is why, despite the associated cost of transporting blood samples to the United States, we opted to use their laboratory services,” Norman said.

“We are excited to offer this test to our expectant mothers, giving them increased peace of mind by providing early opportunities for making vital decisions during their pregnancies.”


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