Combined Test (Nuchal Translucency Scan)
A screening test based on an ultrasound scan and blood test at about 12 weeks (11+3 to 13+6 weeks) has been evaluated in studies of over 200,000 women and found to have a high detection rate across all ages. Our centre is licensed and quality controlled by the Fetal Medicine Foundation in London who have pioneered this modern approach to screening. All scans are performed by a Consultant in Fetal Medicine or a DMU certified sonographer or equivalent and all blood samples are processed by The Doctors Laboratory in London.
How does the test work?
By measuring the thickness of tissue fluid that lies under the skin at the back of the baby’s neck, the Nuchal Translucency, a computer programme can convert this, the length of the baby and the mother’s age into a risk for Down Syndrome, Edward Syndrome and Patau Syndrome for that baby. Because it is based on the appearance of an individual baby, the technique can also be used in twins and triplets etc to give a risk for each baby.
Why do I also have a blood test?
The test has a detection rate of 80% based on scan alone rising to nearly 90% in single pregnancies if blood markers (PAPP-A and free B-hCG) are also measured in a sample of blood taken from the pregnant woman’s arm at the time of the scan. Results based on scan are available on the day and blood tests results are available within a few days.
Although this test is available in the NHS in Wales, they do NOT report risks for Edward Syndrome and Patau Syndrome and their reported detection rate is lower at 85% whereas we report 90%.