NIPT (Non-Invasive Prenatal Test)

Non-invasive prenatal tests are advanced genetic tests that are carried out by taking a small blood sample from the mother’s arm, a simple and safe procedure, with no risk to the baby. They are based on the detection of small fragments of fetal DNA in the maternal blood, which are used to screen for Down’s syndrome and other chromosomal abnormalities

If you are considering having an NIPT, it’s reassuring to know that, unlike an amniocentesis, there is no increased risk of miscarriage. You can have the blood test at the same time as your early pregnancy scan or 12 week ultrasound scan, and results are back within 3-10 working days, depending on which test you opt for. 

It is important to remember that NIPTs are screening tests, not diagnostic tests. This means the results provide a highly accurate estimate of the risk – rather than absolute certainty – that a baby may have a genetic abnormality. While an NIPT is an exceptional tool for reassurance, any high-risk result would require a follow-up diagnostic test (such as an amniocentesis) for a definitive clinical diagnosis.

You can choose to have an NIPT from 9-10 weeks of your pregnancy depending on which test you opt for. We recommend having the test at the same time as an early pregnancy ultrasound scan, a 12 week nuchal translucency scan, or your 20 week anatomy and anomaly scan, and we will take your blood sample at the same time.

Every pregnancy is different, and it is important that you make the right choice according to your needs as parents. We suggest having an NIPT if your baby might be at increased risk of chromosomal abnormalities. 

For example:

• If you are over 35
• If you have had a high probability result from a nuchal translucency scan or your 20 week anomaly scan
• If you have had a confirmed chromosomal condition in a previous pregnancy, particularly after repeat miscarriages
• There is a family or personal history of genetic abnormalities 

We also know how everyone needs differing levels of reassurance and information during their pregnancy. Therefore it’s good to know that NIPTs are available to all parents – not just those in a high-risk category – and no referral is needed. For example, some parents may simply wish to know that there is low risk of foetal abnormality early on, so that they can have peace of mind during the rest of the pregnancy. 

NIPTs are the most up-to-date screening technology currently available and offer the possibility for many parents to avoid having to undergo an amniocentesis. If you have had a high probability result from your combined test at 12 weeks, or you are in a high-risk category, you may wish to have an NIPT before an amniocentesis. 

It’s useful to know that the classic combined 12 week ultrasound scan and blood test is only 75-80% accurate in predicting the risk of Down’s syndrome (Trisomy 21). By comparison, the NIPT is over 99% accurate in predicting the risk of Down’s syndrome. 

However, an amniocentesis is the only way you can be certain of whether or not your baby has any genetic abnormality. During this procedure, a specialist uses a fine needle to gently collect a small amount of amniotic fluid for testing. We always discuss this option carefully with our patients, as it carries a small risk of miscarriage (1 in 100); however, it provides the most accurate and definitive analysis of a baby’s genetic profile.

NIPTs, on the other hand, are completely safe but it’s important to remember that they are screening tests that only evaluate the risk, rather than the certainty, of a baby having a chromosomal abnormality.

We offer a choice of private NIPTs in London, which use the most sophisticated testing technology available. To make it easier to understand the difference between the various tests we offer, we have summarised them in the following chart, to give you as much information as possible so that you can make a decision that’s best for your circumstances.

• Illumina: This test has replaced Harmony in the UK. It is one of the most frequently requested NIPTs and tests for Down’s syndrome, Edwards’ syndrome and Patau’s syndrome (Trisomy 21, 18 and 13 ). Results are reported as low, medium or high risk, with accuracy of more than 99%. You can also learn your baby’s gender if you wish and if there are any sex chromosome anomalies. Results are available within 5 working days.
• Panorama with 22q11.2 deletion: The Panorama NIPT test is similar to Illumina and tests for Down’s, Edwards’ and Patau’s syndrome, gender and sex chromosome anomalies. Panorama also tests for 22q11.2 deletion, an anomaly associated with Di George syndrome. Your report will indicate risk of these abnormalities as low or high giving you added reassurance if your pregnancy is considered high risk. For most high-risk results, your report will also include the positive predictive value. This is the percentage likelihood of the foetus being affected. Results are delivered within 10 working days.
• Panorama Extended: This Extended NIPT test looks at all conditions in the Illumina and Panorama tests plus several microdeletion associated with Angelman syndrome, Prader-Willi syndrome and Cri-du-Chat syndrome. Your report will indicate risk as low or high as well as the positive predictive value. Results are delivered within 10 working days.
• Vistara: The Vistara test varies in scope from the other NIPTs we offer and can be performed in combination with another NIPT for more comprehensive testing. This test screens for 25 single-gene disorders across 30 different genes that are not detectable by standard NIPTs, which instead look at chromosome abnormalities and microdeletions. You will receive a personalised risk report giving a positive or negative for each of the screened conditions. Results are available in 2–3 weeks. 

• Extra chromosomes 21,18,13 (trisomies linked to Down’s syndrome, Edwards syndrome and Patau syndrome respectively)
• Gender (inspecting the X and Y chromosomes) if requested
• Sex chromosomes aneuploidies :45,X (Turner syndrome); 47,XXY (Klinefelter syndrome); 47,XXX (Triple X syndrome); 47,XYY (XYY syndrome)
• 22q11 deletion (DiGeorge syndrome)

• Extra chromosomes 21, 18, 13 (trisomies linked to Down’s syndrome, Edwards’ syndrome and Patau’s syndrome respectively)
• Gender (inspecting the X and Y chromosomes) if requested
• Sex chromosomes aneuploidies: 45,X (Turner syndrome); 47,XXY (Klinefelter syndrome); 47,XXX (Triple X syndrome); 47,XYY (XYY syndrome)
• 22q deletion (DiGeorge syndrome)
• 5p deletion (Cri-du-chat syndrome)
• 15q deletion (Prader-Willi/Angelman syndromes)
• 1p deletion (1p36 deletion syndrome)

• Safety: These tests are completely safe, requiring only a blood sample with no risk to your pregnancy.
• Fast turnaround times: 7 working days from arrival of the blood sample in the laboratory. This means we will have your report ready within 10 days of your blood draw.
• Reliable result rate: An incredibly low failure to get a result rate, at 1.4%. This diminishes to 0.5% after redraw. 
• Early reassurance: NIPTs can be performed from 9 weeks of pregnancy enabling early detection of each condition. However we do recommend you wait until 10 weeks as this really diminishes the risk of a redraw being required.
• Easy to understand: An easy to read report, designed to be clear, easy to understand, and medically precise. It provides your test results in a format that helps understand what was screened for and what the results mean for your pregnancy. The first page of your report includes a clear summary showing the result for each condition as simply low or high risk.

Twin pregnancies: Panorama Base Panel with 22q is available for identical twin pregnancies.

The Vistara test offers you more information than is currently available by standard NIPT testing alone. This test looks for 25 clinically significant genetic conditions which affect aspects of your baby’s overall health, development and growth.

Some conditions remain undetected before birth and do not become apparent until later stages of childhood. The Vistara screens for conditions caused by a single-gene alteration, which are likely to affect your baby and cause them to develop symptoms.

A full list of these conditions can be found here. Some examples are:

• Noonan Syndrome
• Achondroplasia
• Costello Syndrome
• Cardio-Facio-Cutaneous (CFC) Syndrome
• Kabuki Syndrome
• Rett Syndrome

Whilst all pregnancies could benefit from the information provided by the Vistara test, a single-gene NIPT should be considered where:

• The male partner is 40 years old or above
• An ultrasound scan has identified anomalies, including shortened long bones and increased nuchal translucency
• There is a family history of hereditary conditions

Just like other non-invasive DNA tests, the Panorama tests do not negate the need for the 12-week Nuchal scan or the 20 week scan, which allows a close and detailed inspection of your baby's anatomy and provides information that a blood test cannot provide.

Pregnancy management decisions should not be based solely on the result of this test, or of any other NIPT.  They are now a reliable alternative to more invasive tests but any positive findings need to be confirmed by other means (such as CVS, amniocentesis) as well as further genetic counselling. 

The rates of non-reportable results, insignificant findings and false-positive results are extremely low for both Panorama tests. However, results can never be considered 100% accurate; and some abnormalities can go undetected even with the most up-to-date tests.

You can find more detailed information on the Panorama tests on their website here.

Our priority is always to make sure you and your baby are safe. We proceed with your chosen test only if all is going well at that point in your pregnancy. Therefore we always try to combine your early pregnancy scan (carried out at 10-11 weeks) or a 12 week scan with your appointment for the NIPT blood draw.  

In some cases, we will offer a NIPT even if we haven’t carried out a scan at our own clinic. However, if you are less than 13 weeks into your pregnancy, we will ask you to bring the report of your most recent scan, which will have to be no more than 4 days before your blood draw.