At a glance
Looking for the most accurate Down Syndrome screening? Have you considered a Non-Invasive Prenatal Test?
The Integrated Test is Down Syndrome screening that is a more accurate than the 12 Week Nuchal Scan. It combines the results of a scan and blood test during your first trimester with a blood test during your second trimester to produce an integrated result.
• 97% detection rate
• No GP referral required
• Procedure performed by a highly qualified sonographer or consultant
• Appointments available at short notice
• Convenient central London location
You will receive
• Results in 3 days
What happens with your results?
Although greater accuracy is achieved by waiting until 15 weeks to perform the second part of the test, you may prefer to receive your results at an earlier time. See our nuchal scan.
We will call you 3 days after your appointment to let you know your results. We will forward the screening results from the laboratory.
What is it?
The integrated test is an alternative screening test for Down Syndrome to the nuchal scan. This test combines the results of a first trimester scan and blood test with a second trimester blood test to give a single risk estimate.
The test has been developed by Professor Wald and his team at The Wolfson Institute, St Bartholomew’s Hospital, London. Professor Wald is a pioneer of Down Syndrome screening in the UK, and along with the Wolfson Institute, he is internationally recognised for his work in this area.
We provide the expert scanning service for the integrated test and The Wolfson Institute analyse the blood samples.
How does the integrated test work?
The test is performed in two stages. The first stage is performed in the first trimester, no earlier than 11 weeks and two days of pregnancy and up to 13 weeks gestation, as determined by the first day of your last menstrual period or a previous dating scan. The second stage is performed in the second trimester at 15 or 16 weeks of pregnancy. It is also possible to perform this stage up to 22 weeks.
First stage – a scan is performed to measure the size of the baby, its nuchal translucency thickness (the space at the back of its neck) and to check for the presence or absence of a nasal bone. A blood test is also taken at this time for later analysis.
Second stage – a blood test is taken and a follow up scan is offered as reassurance and to confirm all is progressing well.
The data from your first ultrasound scan and results from both blood tests are integrated to produce a final screening result three days after your final blood sample.
The blood tests
The first blood test is used to measure your concentration of PAPP-A and the second blood test is used to measure your concentration of AFP, free beta hCG, inhibin-A and unconjugated estriol. The final screening result combines the visibility of the nuchal translucency measurement, presence or absence of a nasal bone in the scan, plus the levels of the five markers in your blood, together with your age, to estimate your risk of having a Down Syndrome baby.
Why wait until 15 weeks for the test?
By using data obtained in early and later pregnancy the detection rate becomes greater than most first trimester Down Syndrome screening tests. The integrated test will distinguish affected from unaffected pregnancies more accurately, reducing the chance that a Down Syndrome pregnancy is missed as well as reducing the chance that you will need an invasive diagnostic test, such as amniocentesis or CVS.
Although greater accuracy is achieved by waiting until after 15 weeks for a result, you may prefer your Down Syndrome risk to be given at an earlier time. In this case please opt for our nuchal scan.
Or you should consider the Non-Invasive Prenatal Test?
How accurate is the Integrated Down Syndrome Test?
Data from the Wolfson Institute (the laboratory) has shown that in screening for Down Syndrome, the integrated test with nasal bone achieves a detection rate of 97%. The detection rate is the number of babies with Down Syndrome predicted by a positive test. This means that 3% of women with pregnancies affected with Down Syndrome will receive a falsely reassuring screen negative result which is incorrect.
The test achieves the high detection rate with a low screen positive rate of 1% - this is the number of babies who did not have Down Syndrome but were considered high risk by the test. Therefore 99% of women whose pregnancies are not affected with Down Syndrome will receive a screen negative result.
Where can I read more?
For copies of the Integrated Test information leaflets please click on the links below. The documents are provided in PDF format.
Download a copy of the Down Syndrome age risk chart.