Some multi-marker screening is now available via the NHS.
Detection rate is >75% and the positive rate <3%.
At Leeds Screening Centre; Addmark®, Nuchal+ and Genmark use additional markers to increase risk accuracy.
Addmark® uses up to 2 ultrasound markers; nuchal translucency (NT) and nose bone (NB) and is combined with up to 8 blood markers to give an
Addmark® detection rate of 93% for a
positive rate of 0.6%
Ductus venous (DV) blood flow is checked but not used in the calculation currently.
Nuchal+ uses ultrasound alone with up to 3 ultrasound markers; nuchal translucency (NT), nose bone (NB) and ductus venous (DV) blood flow and gives a detection rate of 89% for a postive rate of 2.8%
Our
Genmark screening is a 2nd trimester screening test and is available for those patient's who have missed the timing for a 1st trimester screening. Up to 2 ultrasound markers; nuchal fold (NF) and nose bone lenght (NBL) are combined with 4 blood markers to give a
Genmark detection rate of 80% for a
positive rate of 2.7%
Why have your Down’s Syndrome screening at LSC ....
At LSC all ultrasound clinical staff are accredited by the Fetal Medicine Foundation (FMF) and have a number of years experience specifically in this type of screening. Ultrasound marker audit data has to be submitted and verified on an annual basis with the FMF. All specialists are accredited to look at the following ultrasound markers and a full 11 – 13 week anatomy check is performed on your baby at the same time.
..... because to get the most accurate risk assessment LSC look at all the following:
Nuchal Translucency
This is a measurement of the fetal neck skin. In 95% of Down's, 70% of Edwards, 85% of Patau's and 5% of chromosomally normal fetuses, the fetal NT is increased.
Nose Bone
At 11-13+6 weeks the nasal bone (NB) is not visible by ultrasound in about 60% of fetuses with Down's syndrome, 50% with Edwards , 40% with Patau's and in about 2% of chromosomally normal fetuses. Therefore, the presence of the fetal nasal bone will reduce the risk for Down's.
Ductus Venosus
When you have your scan at LSC, our specialists use ultrasound doppler to assess blood flow in the ductus venosus (DV) which is a blood vessel in the baby’s tummy and has a characteristic waveform. At 11-13+6 weeks reversed flow in the DV is observed in about 3% of chromosomally normal fetuses, 65% of fetuses with Down's, 55% of fetuses with Edwards and 55% of fetuses with Patau's.
Reversed flow in the DV is associated with cardiac defects and therefore, if this pattern is noted at the 11-13+6 weeks scan, it is important to carry out a good fetal cardiac examination at 20–23 weeks.
Anatomy Check
Importantly with all multi-marker screening the ultrasound scan at LSC also dates the pregnancy, checks the fetal anatomy, (head, stomach, bladder, cord insertion, arms and legs) to rule out a large number of fetal abnormalities.
Certain major defects have a very strong association with chromosomal abnormalities. By checking the head, body anatomy and presence of the limbs, the vast majority of structural defects are ruled out. The baby’s face, heart and spine are best checked at the 20–23 week scan when the baby has grown larger.
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Check with your hospital what their test offers and what markers they use
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Down's syndrome The most common cause of severe learning disability. There are associated medical problems: but many are healthy and have a good life span.
Edwards' syndrome Less common than Down's syndrome; nearly all affected die in early infancy.
Patau's syndrome A rare chromosomal disorder.
Spina bifida Failure of the neural tube to close causes physical disability but generally no mental handicap. Gross defect can sometimes be seen at the 11-13 week scan but is usually checked in more detail at the 20-23 week scan.