Genetic testing during pregnancy
From 14th September 2023, Starlight Ultrasound has had access to the Illumina VeriSeq Non-invasive prenatal testing (NIPT) Solution v2 as a new and improved NIPT version of the Harmony NIPT assay.
The Illumina VeriSeq NIPT offers analysis for the same conditions as the Harmony NIPT but with some additional benefits such as a lower failure rate (less than 2%) and only one blood tube being required – this is sufficient to enable a repeat test if necessary.
We have noticed a quicker turnaround of results, giving people faster answers and reassurance.
Samples are still collected by courier and taken straight to the TDL lab for prompt processing.
What NIPT Tests For
The test looks to detect the following conditions:
- Trisomy 21, also called Down syndrome, Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau syndrome).
- Sex chromosome aneuploidy panel option assesses risk for XXX, XYY, XXY (Klinefelter syndrome), and a missing X chromosome in a girl (Turner syndrome).
In addition, NIPT can assess fetal gender. This is optional at no additional cost and can be decided when the sample is taken.
One of the main advantages of NIPT is that it provides fewer false-positive and false-negative results than combined first trimester screening for trisomy 21, 18 and 13.
It is important to note that NIPT is a screening test and does not provide a definitive genetic diagnosis, as NIPT cannot differentiate potential chromosome differences between the placenta and fetus. A definitive genetic diagnosis of the fetus requires cytogenetic analysis of either amniotic fluid or chorionic villus sampling (CVS).
As the testing is non-invasive and involves taking a single blood draw sample from the mother, the pregnancy is not put at risk of miscarriage, or from other adverse outcomes that are associated with invasive testing procedures such as amniocentesis.
Limitations of NIPT
The VeriSeq NIPT Solution v2 is not validated for use in pregnancies with more than two fetuses, fetal demise, mosaicism, partial chromosome aneuploidy, triploidy, translocations, maternal aneuploidy, transplant or malignancy. VeriSeq NIPT Solution v2 does not detect neural tube defects. Certain rare biological conditions may also affect the accuracy of the test.
For twin pregnancies, HIGH PROBABILITY test results apply to at least one fetus; male test results apply to one or both fetuses; female test results apply to both fetuses. Due to the limitations of the test, inaccurate results are possible.
A LOW PROBABILITY result does not guarantee that a fetus is unaffected by a chromosomal or genetic condition. Some non-aneuploid fetuses may have HIGH PROBABILITY results. In cases of HIGH PROBABILITY results and/or other clinical indications of a chromosomal condition, confirmatory testing is necessary for diagnosis.
Note that, in twin pregnancies, sex chromosome (X and Y) analysis can determine fetal sex but not sex chromosome conditions. This test is not suitable in the case of a vanishing twin. The sex of twins will be reported as one result. If male, one or both of the twins will be male. If female, both twins will be female.
The test does not assess risk for mosaicism, partial trisomies or translocations.
Results will be ready in approximately 2–4 days with a one-page report which summarises the screening assessment for each condition.
It can take place before or after the NHS dating scan which will include a measurement of nuchal translucency, nasal bone and other important factors.
Who can have this test?
NIPT is available from 10 weeks into pregnancy and at Starlight, it includes both an ultrasound scan and the blood test. It is available to singleton or twin pregnancy, including those conceived naturally or by IVF using the patient’s own egg or a donor egg. This test is not suitable in the case of a vanishing twin. It can be carried out at any gestation from 10 weeks so there is no cut-off date.
It is not limited to high-risk or low-risk pregnancies and can be booked directly without previously having had a scan or not.
You can book online 24/7 or you can phone or call in to either of our clinic locations to book the NIPT or any other appointment. Or call 01612600 for urgent / priority bookings.