IONA NIPT (Non-Invasive Prenatal Testing)
The IONA® test is a non-invasive prenatal test for pregnant women which estimates the risk of a fetus having Down’s syndrome (T21), Edwards' syndrome (T18) and Patau’s Syndrome (T13). The IONA® test is an advanced screening test carried out on a small blood sample taken from the mother’s arm with no risk of miscarriage. Fetal sex determination is available optionally in regions where fetal sex determination is permitted. Please ask your healthcare professional for further information.
- Safe: non-invasive with no risk of miscarriage
- Fast: results available in 2-5 working days from sample receipt in the laboratory
- Accurate: Overall 99.8% detection of trisomy conditions (trisomy 21, 18 and 13)
- Local: the IONA® test is processed at Yourgene Genomic Services based in Manchester, UK. The clinical laboratory is registered with the Care Quality Commision (CQC) an independent regulator of health and social care in England.
- Quality: the IONA® test is a regulated screening test which is CE marked
What is NIPT?
A non-invasive prenatal test (NIPT) is an advanced screening test using DNA in the mother's blood to estimate the risk of a fetus having Down’s syndrome, Edwards' syndrome and Patau’s syndrome. There are many different NIPTs on the market, but the majority will screen for these three syndromes. Edwards’ and Patau’s syndrome are much rarer than Down’s syndrome but are very serious and many affected babies die before or soon after birth. Trisomies occur when three, instead of the usual two, copies of a chromosome are present.
Traditional screening offered during the first trimester of pregnancy is currently called the Combined Test. This is an ultrasound scan to measure the nuchal translucency (NT), combined with a blood test. This is less accurate than NIPT, detecting about 85% of babies with Down’s syndrome. The IONA® test has a higher detection rate than the Combined Test. The IONA® test is also better able to exclude false positives. This is when the test reports the baby is at a high risk of having Down’s syndrome but is actually unaffected. The IONA® test is much better at ensuring the babies identified are truly high risk. This allows the doctor to only refer the mother for an invasive test when it is highly likely that the baby is affected by a trisomy. This means fewer pregnant women will undergo unnecessary invasive follow-up procedure such as amniocentesis or CVS which can be stressful, painful and may carry a small risk of miscarriage.
How does it work?
From 10 weeks gestation a small blood sample is taken from the mother’s arm and sent to Yourgene Genomic Services in Manchester, UK for analysis with the IONA® test. During pregnancy, the placenta leaks cell-free DNA which circulates in the maternal bloodstream. As a result, a maternal plasma sample contains a mixture of placental and maternal cell-free DNA. This cell-free DNA from the mother’s blood is extracted and the test is performed on this small amount of DNA. The IONA® test directly measures the amount of cell-free DNA and can detect small changes in the DNA ratio between the maternal and placental-fetal cell-free DNA when a fetal trisomy 21, 18 or 13 is present.
The IONA® Software for analysis calculates the relative amount of chromosomes 21, 18 and 13 to produce a risk score to predict the presence of a trisomy. This figure is then combined with the prior risk (by default this is the mother’s age but the result of the First Trimester Combined Test (FTCT) can be used instead) to calculate the probability of the fetus being affected.
Who can have the IONA® test?
Suitable for:
- Pregnancies from 10 weeks gestation
- Singleton or twin pregnancies
- IVF, donor egg or surrogate pregnancies
Unsuitable if the mother:
- Has received an organ transplant
- Has cancer
- Carries a chromosomal imbalance
- Had a transfusion of heterologous cells in the last year
- Has complete or partial monosomy X (Turner syndrome)
Clinical Performance
IONA® Nx validation study*
Test performance observed following validation metrics for singleton and twin pregnancies
| Sensitivity | Specificity | |
|---|---|---|
|
Trisomy 21 |
>99.99% |
>99.99% |
|
Trisomy 18 |
>99.99% |
>99.99% |
|
Trisomy 13 |
>99.99% |
>99.99% |
* The Validation performance has been demonstrated by evaluating 472 clinical samples from singleton and twin pregnancy and comparing to a reference result of an amniocentesis or chorionic villus sampling (CVS) sample or a birth outcome.
| Condition | Sensitivity | Specificity |
|---|---|---|
| XO (Turner Syndrome) |
>99.99% (15/15) 95% CI: 78.2 – 100% |
>99.99% (428/428) 95% CI: 99.1 – 100% |
| XXY (Klinefelter syndrome) |
>99.99% (4/4) 95% CI: 39.8 – 100% |
99.5% (437/439) 95% CI: 98.4 – 99.9% |
| XYY (XYY Syndrome) |
N/A | >99.99% (443/443) 95% CI: 99.2 – 100% |
| XXX (Trisomy X) |
>99.99% (1/1) 95% CI: 2.5 – 100% |
>99.99% (442/442) 95% CI: 99.2 – 100% |
| Trisomy | >99.9% (3/3) 95% CI: 29.2 – 100% |
99.3% (439/442) 95% CI: 98.0 – 99.9% |
| Monosomy | N/A | >99.9% (442/442) 95% CI: 99.2 – 100% |
The Validation performance has been demonstrated by evaluating 443 clinical samples from singleton and comparing to a reference result of an amniocentesis or chorionic villus sampling (CVS) sample or a birth outcome.
This has been demonstrated using the IONA® Nx cfDNA Library Preparation DX kit and the IONA® analysis software version 2.0.2. Data held on file by Yourgene Health Plc.
A comprehensive test panel
The IONA® test is available as a clinical service at Yourgene Genomic Services, based in Manchester, UK. The IONA® test is a CE-IVD prenatal screening test which is offered to pregnant women to estimate the risk that their fetus may be affected with:
- Autosomal Aneuploidies (AAs)
- Trisomy 21 (Down's syndrome)
- Trisomy 18 (Edwards’ syndrome)
- Trisomy 13 (Patau’s syndrome)
- All additional trisomies (optional)
- All monosomies (optional)
- Fetal sex determination (optional)
- Sex Chromosome Aneuploidies (SCAs) (optional)
- 45,X (Turner syndrome)
- 47, XXX (Trisomy X)
- 47,XXY (Klinefelter syndrome)
- 47,XYY (Jacob's syndrome)
Results
The results of your IONA® test should be discussed in detail with your healthcare professional.
IONA® test results are reported as:
- Low Risk: it is very unlikely the pregnancy is affected by trisomy 21, 18 or 13
- High Risk: the pregnancy is at increased risk for trisomy 21, 18 or 13 and the result should be confirmed by a follow-up invasive procedure, such as an amniocentesis or CVS.
- No Result: very occasionally there is insufficient placental DNA in the sample to obtain a result. Women may be asked back by the healthcare provider for a further blood sample.
Fetal sex determination
The IONA® test offers optional testing to determine the baby’s sex. A “sex determination failure” result may be reported if there is insufficient data to support the sex determination analysis. A failed result does not reflect on the quality of any other result generated by the IONA® test.
Please note that the sex determining technique is not a screening test for rare sex chromosome conditions and is not currently available for multiple births except for identical (monochorionic) twin pregnancies. We therefore recommend that fetal sex determination is confirmed by ultrasound.
Fetal sex determination is only available for singleton and monochorionic twin pregnancies. It is only offered in regions where fetal sex determination is permitted.
For more information please visit the Yourgene Health website.
Frequently Asked Questions
-
How accurate is the IONA® test?
The IONA® test has an overall accuracy of 99.8% and a less than 0.5% failure rate for Down’s syndrome, Edwards’ syndrome and Patau’s syndrome.
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What is the false positive rate?
Less than 1% of pregnant women may receive a high risk result from the IONA® test and then go onto to have a follow-up invasive test which confirms that the fetus is not affected with trisomy 21, 18 or 13.
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How is the sample taken?
A simple blood sample is taken from your arm by a healthcare professional after you have been pregnant for at least 10 weeks.
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What is the current method of screening?
Currently most healthcare systems offer pregnant women the combined test which includes a fetal ultrasound and blood test performed at about 11-13 weeks into the pregnancy. The ultrasound looks at multiple aspects of the developing fetus, but particularly at the skin fold at the top of the spine where it meets the skull, this is called the Nuchal Translucency (NT). The blood test measures the levels of two hormones: hCG and PAPP-A. The current combined test has a ~85% detection rate and ~5% false positive rate.
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Is the IONA® test replacing the 11-13 week dating scan?
No, it is recommended that you still have this dating scan at 11-13 weeks to assess the baby's growth and development. The IONA® test or any other non-invasive prenatal DNA screening test will not replace this dating ultrasound.
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Is the IONA® test 100% conclusive?
It is not 100% conclusive due to naturally occurring biological instances where the fetal DNA differs from the placental DNA. The IONA® test is a screening test.
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How long will it take to get the results?
Once the sample is received at the laboratory it can take between 2-5 working days to perform the test. The data from the laboratory test is entered into the IONA® analysis software and an easy to interpret result report is generated and given to your healthcare professional such as a consultant or midwife. This report will then be discussed with you by your healthcare professional.
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What are my options if I have a high-risk result for a trisomy?
If you get a “high risk” result, you will be contacted by your consultant or midwife. The next steps will be determined in consultation with your healthcare provider. All high-risk results should be discussed with your healthcare provider.
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Can I have the IONA® test if I have twins?
The IONA® test is suitable for twin pregnancies. However, in dichorionic twins, the test sensitivity is reduced from >99% to about 95%. Dichorionic means there are two placentas, which occurs with non-identical twin and some identical twin pregnancies.
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Can I have the IONA® test if I have had a blood transfusion?
The accuracy of the IONA® test may be affected if the mother has undergone a non-leucocyte depleted blood transfusion in the last 12 months. Suitability for the IONA® test should be discussed with your healthcare professional.