Illumina NIPT

The Illumina prenatal test offers a high degree of reassurance for women who are at risk of chromosomal abnormalities. The test can be done from 10 weeks onwards and tests for the following:

• Down’s syndrome (trisomy 21), Edwards’ syndrome (trisomy 18), and Patau syndrome (trisomy 13)
• Gender, if you wish to find out
• Sex chromosomes anomalies (also known as aneuploidies)

The Illumina test is the most popular non-invasive prenatal screening test among parents, due to its accuracy and reliability. You may hear it referred to generically by your antenatal care team as a ‘non-invasive prenatal test (NIPT)’ or a ‘non-invasive prenatal diagnosis (NIPD)’. However, it’s useful to know that it is not the only prenatal screening test available. Here at the Medical Chambers Kensington, we also offer the Panorama NIPT and Panorama Extended Panel, which also provide high levels of accuracy.

We usually recommend the Illumina test if you are at an increased risk of chromosomal abnormalities. For example: 

• If you are over 35 
• If you have had a high probability result from a 12 week nuchal translucency scan (combined test) or your 20 week anomaly scan
• If you have had a confirmed chromosomal condition in a previous pregnancy
• There is a family or personal history of genetic abnormalities 
• If you have had a low-risk pregnancy, you may still wish to have the Illumina test for an accurate prediction of risk of Down’s syndrome – the most common chromosomal condition

You can choose to have the Illumina test from between 10 and 22 weeks of your pregnancy. We recommend having the test at the same time as your early pregnancy ultrasound scan or 12 week nuchal translucency scan.

This means we can carry out an advanced anatomical examination and check for any major chromosomal anomalies early on in your pregnancy. Alternatively you can choose to come in for your Illumina blood test at a separate time, convenient to you.

Our exceptional levels of care mean that we only carry out the Illumina test from 10 weeks onwards and only if your pregnancy is progressing well at that point. Therefore, we always try to combine either your early pregnancy scan (10-11 weeks) or your 12 week nuchal translucency scan with your appointment for the Illumina blood test.

In some cases, we offer the Illumina test even if we haven’t carried out the ultrasound 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 test. 

We first carry out your ultrasound scan  before the blood test, to make sure that your baby is healthy, growing well and has a strong heartbeat. This will usually either be at 10-11 weeks or at 12 weeks.

Once you’ve had your ultrasound scan and had time to discuss the different prenatal test options with one of our specialists, we carry out a simple blood draw from your arm. 

The blood sample is then sent off to a state-of-the-art UK laboratory to be analysed and processed within a few days. As it’s a screening test, the Illumina test results show whether you have a high, medium or low probability of Down’s, Edwards’ or Patau syndrome. 

Our prenatal ultrasound specialist will review your results as soon as they arrive and will call you if a high risk is identified. We will also send you and your doctor a copy of your report.

During pregnancy, the baby produces tiny amounts of ‘cell free’ DNA, which circulate in the maternal bloodstream. This occurs during the natural breakdown of foetal cells, mainly from the placenta. 

By taking a simple blood sample from your arm in early pregnancy, specialists can analyse this DNA in a high specification lab and screen for any abnormalities in the baby’s chromosomes. 

The Illumina prenatal test screens for chromosomal conditions called trisomies, which occur when there are three copies of a particular chromosome instead of the usual two. The test screens for trisomy 21 (Down’s syndrome) and trisomy 13 and 18 (Edwards’ and Patau syndromes). 

We understand how difficult a high probability result may be. Our specialists will phone you with the result and spend as much time as you need answering any questions you have at that point. It is important to remember that whilst the Illumina test is very accurate, like all NIPTs it remains a screening test, not a diagnostic one – for example, false positives and false negatives can occur for a variety of reasons. 

Before you make any decisions, we always recommend genetic counselling and that any finding should be confirmed by other diagnostic tests, such as CVS (chorionic villus sampling) or amniocentesis. 

These tests are the only way to determine with 100% accuracy if your baby has Down’s syndrome or any other chromosomal condition, as they analyse the baby’s chromosomes, rather than the cell-free DNA (cfDNA) in the mother’s blood. However, these tests carry a potential risk of miscarriage.