Non-Invasive Prenatal Testing (NIPT) in London

Non-invasive prenatal screening is an advanced screening test predominantly for 3 chromosomal anomalies: Down’s Syndrome (Trisomy 21 – >99% detection rate) Edward’s Syndrome (Trisomy 18 – 97.4% detection rate) Patau’s Syndrome (Trisomy 13 – 93.8% detection rate) Harmony NIPT published the figures above which represent detection rates. The test is highly accurate with false positive rates <0.1% for all 3 trisomies. Detection and false positive rates are calculated at a risk cut-off of 1/100. The test can also detect the fetal sex with >99% accuracy. Use our NIPT PPV calculator to understand the predictive power of each test.

The Basic PrenatalSafe NIPT at London Pregnancy Clinic offers a highly reliable and efficient screening option specifically for Down’s syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). Here’s why it stands out: Superior Performance: The Basic PrenatalSafe NIPT is designed with a focus on accurately detecting the most common chromosomal abnormalities, giving parents the reassurance they need. Minimal Sample Requirement: This test requires only one tube of blood, which is less than what most other NIPT options require, making the process more convenient and less invasive. Quick Results: With a UK-based lab, the test delivers results in just 2-5 working days, ensuring that parents receive timely information. Low Redraw and No-Call Rates: The test boasts a low redraw rate of less than 2% and an impressively low no-call rate of 0.5%, minimizing the need for repeat testing. Accurate Fetal Sex Determination: For parents interested in knowing their baby’s sex, this option is available with high accuracy. Effective in Complex Situations: The Basic PrenatalSafe NIPT is also effective in cases of ‘vanished’ twins, where other NIPT options may not be applicable.

10 weeks is the best time for your NIPT because:

• You prefer to be reassured regarding Down’s syndrome as early as possible
• We perform your earliest fetal structural anomaly scan at 10 weeks which will exclude severe not-chromosomal defects
• In case of no-call NIPT results of the test you have plenty of time to retake the test and have alternative screening for Down’s syndrome by Combined Test
• In case of high-chance NIPT results you can perform CVS (invasive test) to confirm or exclude the chromosomal problem at earliest possibility (usually at 11-12 weeks).
• In case of an abnormal finding in our 10 Week Scan, we will assist you in an urgent referral to Fetal Medicine Unit without wasting your time or money for inappropriate NIPT. It is well-recognised that NIPT is unsuitable test in the case of structural fetal anomaly

It is possible to perform Panorama Test from 9 weeks, however in this case structural assessment of the baby can be limited

We recommend taking the NIPT along with our comprehensive early anomaly scan (10-week scan) as soon as possible – 10 weeks. Early detection of either chromosomal or structural anomalies allows more time in terms of pregnancy management for those conditions. If your sample fails, you have plenty time for redraw.

If you’re unsure about the age of your pregnancy, we strongly recommend performing a viability scan with us at around 7-8 weeks of your gestation. The viability scan will date your pregnancy and we can arrange the earliest possible appointment for your NIPT. If you’d prefer not to have the viability scan, please allow a couple of days after the 10-week mark to avoid repeat appointments for drawing the bloods. You can also miss all the advantages of the 10-week scan, because your baby will be too young to have a proper early anomaly scan.

In theory, NIPT is available from 9-40 weeks, but it is strongly recommended to take the test in the first trimester, as the pregnancy management options in the second trimester can be very limited.

PrenatalSafe NIPT, developed by European NIPT leader Eurofins, employs cutting-edge genomics technology and a proprietary test algorithm, ensuring reliable screening for common chromosomal anomalies like Down’s syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). PrenatalSafe stands out due to its minimal maternal blood requirement (just one tube) and impressively low no-call rates (less than 2%). This makes PrenatalSafe an extremely effective blood test for Down syndrome. It’s uniquely effective in situations involving ‘vanished’ twins where other NIPT options may not apply. Additionally, PrenatalSafe offers high accuracy in optional fetal gender determination.

PrenatalSafe is our top choice for NIPT in London, driven by its utilisation of advanced technology, minimal no-call results, and a swift turnaround time, thanks to its UK-based lab facility.

Panorama AI is an American variant of basic NIPT. The Panorama test was developed by Natera (US), a pioneer in the field. The newly upgraded Panorama AI algorithm uses a combination of artificial intelligence (AI) and Natera’s proprietary genetic methodology to improve accuracy and the positive predictive value for an extended range of chromosomal conditions. Panorama NIPT represents a slightly extended basic NIPT panel and includes screening for Down, Edwards and Patau syndromes, sex chromosomes aneuploidies, triploidy, and DiGeorge (22q del) screening. Panorama NIPT also works from 9 weeks of gestation.

UNITY is the principal new concept in NIPT, recently developed by BillionToOne Inc. in California, and is now getting significant attention in the US. As a new player on the market, UNITY offers a cost-effective option for basic screening of Down syndrome and other common chromosomal abnormalities. However, the results from UNITY come back relatively late, which offsets its cost advantage.

UNITY Carrier Screen screens for up to 14 inherited conditions — including cystic fibrosis, spinal muscular atrophy, sickle cell disease, thalassaemia, Fragile X syndrome and Tay-Sachs disease. UNITY Carrier Screen NIPT is included in our SMART Test® Plus option, providing a comprehensive solution for screening both de novo and inherited diseases.

Harmony Test was Roche’s brand name for NIPT. It was the first NIPT introduced in London over 10 years ago. The test was extensively marketed and became very popular in the UK. TDL Genetics performed this NIPT in London. Unfortunately, when compared to other brands of NIPT tests (such as PrenatalSafe or Panorama), Harmony Test showed poor reliability and performance, damaging its reputation as the best NIPT. In 2023, TDL terminated this service due to problems with the test performance.

Please find a comparison table between the tests below.

Our specialists will initially conduct an anatomical examination of the baby to check for structural anomalies and take some measurements for the NIPT test. Once the clinician is satisfied with the baby’s normal structural examination, they will proceed with a consultation about NIPT to answer your questions about every aspect of the test. Finally, our friendly phlebotomist will take the mother’s blood sample from the arm – just like any routine blood test you may have done elsewhere. Our staff then process the maternal blood samples and will send them to the lab soon after your appointment. Now all there’s left to do is to wait for a call from us!

Ultrasound is a vital part of fetal screening. The laboratory requires a confirmation of viability and gestational age by the clinic submitting each NIPT NIPT is a highly effective screening test for 3 chromosomal anomalies plus some other genetic conditions (panorama only), however it is unable to screen for structural anomalies such as heart or brain defects which are more common and often more serious than Down’s syndrome. Here at London Pregnancy Clinic, we specialise in early detection of fetal anomalies, the fetal heart and the fetal brain. We can detect some severe fetal anomalies as early as at 10 weeks. Visit our scans page to find out which scan you will be having along with NIPT. Generally, we believe that our 10-week scan is the best option. If you choose to have a panorama test at 9 weeks, we will also perform an expert structural scan for your baby (embryo), however this scan will be understandably limited due to small size and developmental immaturity of the baby.

With our expertise and technology, we can screen for structural anomalies from 10 weeks (approximate prevalence in the first trimester): Acrania (1:1,000) Alobar Holoprosencephaly (1:1,300) Spina Bifida (1:2,000) – included in SMART Test® only Absence of arms, hands, legs or feet (1:2,000) Encephalocele (1:5,000) Exomphalos (Omphalocele) with liver (1:3,500) Amniotic Band Anomaly (1:7,000) Body Stalk Anomaly (1:7,500) Sirenomelia (1:60,000) Conjoined Twins (1% of monochorionic twins) In comparison, the prevalence of the chromosomal conditions screened for by NIPT (England 2021): Down Syndrome (1:336) Edward Syndrome (1:1086) Patau Syndrome (1:3048) If you take the test at 12+ weeks we are able to screen by ultrasound for >100 structural fetal anomalies, however we may lose few advantages of early NIPT.

We understand that expectant parents make a significant decision to have Non-Invasive Prenatal Testing (NIPT). London Pregnancy Clinic (LPC) is a leading provider of NIPT in London, offering an unmatched combination of expertise, quality, and the widest selection of tests. Due to our high volume of NIPT testing, we have been able to continuously monitor the performance of different NIPT providers and select only the most accurate and reliable tests. Our rigorous selection process ensures that we work only with internationally recognised laboratories, avoiding tests with historically high failure rates.

Why Choose Us?

• Carefully Selected NIPT Providers
  We offer only the most reliable NIPT tests from accredited international laboratories. We do not use labs with high failure rates (e.g., Harmony Test) or unaccredited providers (e.g., Concepto). We maintain direct contact with the labs for efficient test processing and troubleshooting.
• Expert-Led Services
  All services are performed by fetal medicine specialists (doctors and sonographers) with extensive experience in prenatal screening. Pre-NIPT counselling is mandatory for every patient to ensure informed decision-making. Option for pre-NIPT genetic counselling with a certified genetic counsellor for complex cases. Honest and transparent discussions about the advantages and limitations of different NIPT options.
• The Only Clinic Offering an expert Pre-NIPT Ultrasound Scan
  Before any NIPT blood draw, we perform an early anomaly scan (10-Week Scan or Early Fetal Scan) to identify cases that would not benefit from NIPT. This approach helps avoid unnecessary NIPT testing and ensures the most appropriate screening pathway for each patient.
• The Widest Selection of Advanced NIPT Tests
  From basic PrenatalSafe (T21, T18, T13) to the most advanced NIPT panels, including KNOVA and PrenatalSafe Complete Plus. Specialised NIPT options for high-risk pregnancies, such as increased nuchal translucency (NT).
• Fast Turnaround and Reliable Test Processing
  Strict turnaround time (TAT) monitoring to ensure timely results. Same-day appointments available for urgent cases.
• Clear Pathways for High-Probability (High-Chance) Results
  Immediate in-house genetic counselling for high-probability results. Free targeted fetal rescan with our expert fetal medicine specialists. Guided referral to diagnostic testing (CVS/amniocentesis) when necessary.
• Patient-Centred Approach & Flexible Services
  Competitive pricing without compromising quality. Parents are encouraged to take time to decide on their preferred NIPT and return for the blood draw later. Ongoing service improvements to provide the best prenatal screening experience.
• Development of the Most Advanced Screening Panel – SMART Test®
  SMART Test® combines cutting-edge ultrasound and genomics, offering the most comprehensive screening package available. The only early screening that integrates early anomaly scans, expert fetal medicine review, and advanced extended NIPT.
• Follow-Up Early Fetal Scan at 14–16 Weeks
  We offer an optional follow-up scan to detect structural anomalies not covered by NIPT. This additional screening significantly increases the accuracy of fetal health assessments.
• Convenient Locations Across London
  Clinics in The City of London and West London, making access easier for parents across the capital.

With London Pregnancy Clinic, you can be confident that you are receiving the highest standard of NIPT services, backed by expert medical oversight and advanced technology.

It’s important for us that you understand the terminology we use for screening tests:

• Detection rate is defined as the fraction of all patients who have the disease and are called positive by the screening test.
• Positive Predictive Value or PPV is the proportion of the ‘true positives’ as a proportion of all positive results.

As a practical example, the majority of NIPT tests have at least 90% PPV for Down’s Syndrome, meaning that 90% of the fetuses identified as ‘High Probability’ will statistically have the condition. However, the limitation of the test is that in 10% of the cases, it will result in a ‘false positive’ meaning that the test will return a ‘High Probability’ result for a fetus that doesn’t have Down’s Syndrome.

That’s why, for every High Probability result we would refer the patient for a diagnostic test such as CVS or Amniocentesis to verify the results. In the past there has been confusion about certain aspects of NIPT – please see this notice.

If any of the above still unclear to you, please get in touch with us via email or phone and our friendly staff will be happy to run you through the characteristics of the test. We wrote a special blog post about understanding the statistics of the NIPT test, if you would like to find out more, click here.

Read more in our Blog

Non-invasive prenatal testing (NIPT) or alternatively non-invasive prenatal screening (NIPS) is a screening method for determining the chance that a baby will be born with Down’s syndrome or other chromosomal anomalies. NIPT is based on the assessment of small DNA fragments from a baby’s placenta (named ‘cell-free DNA’ or ‘cfDNA’) that are disseminated in the blood of every pregnant mother. Placental cfDNA is usually identical to the DNA of the baby and testing it provides an opportunity for early detection of particular chromosomal anomalies without harming the baby.

The Harmony Test was a well-known NIPT brand by Ariosa/Roche. The Harmony Prenatal test was a trade name of the cfDNA test. We had the experience of using Harmony for many years. The Harmony Test performed by TDL in London in the last years suffered from a high rate of test failure and inconclusive results. Many our patients were unsatisfied by the test performance. In a dramatic move at the end of August 2023, TDL announced the termination of the test performance in a very short warning period of just two weeks.

Panorama AI NIPT (non-invasive prenatal screening) is an extended basic NIPT based on state-of-the-art algorithms. It has a lower sample failure rate compared with the Harmony Test. The limitation of Panorama NIPT is its long results reporting time (up to 10 working days), which is due to sample shipping to a US-based lab.

Although cfDNA is a relatively new genetic test, it has been proven to be superior to any other screening tests for Down’s syndrome, including the combined screening test (CST) used by the NHS. However, NIPT can detect a relatively small proportion (about 15%) of all fetal anomalies, because the vast majority of fetal anomalies are physical (structural) and not chromosomal.

NIPT is a screening test, meaning that NIPT cannot give a definitive answer about whether a baby has Down’s syndrome or other tested chromosomal conditions. If the results are positive (high chance) follow-up invasive testing is needed to get a definite diagnosis. Any invasive testing carries a small risk of miscarriage.

SMART Test® – KNOVA is one of the most advanced screening packages we offer. The KNOVA NIPT component is provided by Fulgent Genetics and screens for around 100 anomalies and syndromes using a carefully curated panel, which helps keep false-positive results low. It uses cutting-edge genetic technology, has a no-call rate of under 1.5 per cent, and returns results in about 7–10 working days — similar to Panorama.

What makes our SMART Test® unique is that it combines this advanced NIPT with an expert early anomaly scan and fetal medicine review in a single appointment, so both chromosomal and structural concerns are addressed together. It is available at London Pregnancy Clinic from 10 weeks. To learn more about the genetic screening involved, see our KNOVA NIPT page, or ask our team which package best fits your pregnancy.

The KNOVA NIPT report presents its performance statistics for each condition it screens rather than as a single overall figure. For every result it sets out the detection rate (how often the test correctly identifies an affected pregnancy) and the positive predictive value, or PPV (the chance that a ‘high-probability’ result reflects a truly affected baby). Because KNOVA screens for around 100 anomalies and syndromes using a curated panel, these per-condition figures matter more than a headline number.

At London Pregnancy Clinic, KNOVA is offered as part of our SMART Test®, and our specialists will talk you through the full sample report before you decide, explaining exactly what the statistics mean for your pregnancy. When your own results are ready, a clinician reviews them and calls you to interpret each figure in plain language. If you would like to understand the numbers in more depth, our team can arrange pre-test genetic counselling so you feel fully informed before booking.

Many parents choose PrenatalSafe NIPT because it combines advanced whole-genome sequencing (WGS) with reliable, well-proven performance for Down’s syndrome (T21), Edwards’ syndrome (T18) and Patau’s syndrome (T13). It has a low no-call rate of under 2 per cent, needs only a small maternal blood sample, and returns results quickly through its UK-based laboratory. It is also one of the few tests that can be used in pregnancies affected by a vanishing twin.

At London Pregnancy Clinic, PrenatalSafe is our first-choice basic NIPT and a trusted replacement for the discontinued Harmony Test. Every appointment includes an expert early anomaly scan and a consultation, so our specialists can confirm the test is right for you before any blood is taken. You are welcome to take time to decide and return for the blood draw later. You can read more on our PrenatalSafe NIPT page or speak to our team about which option suits your pregnancy.

Yes, basic PrenatalSafe NIPT is a better alternative to the Harmony Test, offering greater reliability, improved test performance, and a lower no-call rate. Here’s why:

• Improved Reliability and Lower No-Call Rate
  The Harmony Test had high no-call rates (around 6%, increasing to 33% in 2023 before it was discontinued by TDL). Basic PrenatalSafe NIPT has a low no-call rate (<2%), reducing the need for repeat testing and ensuring faster, more reliable results.
• Same Core Screening but Enhanced Accuracy
  Like the Harmony Test, basic PrenatalSafe NIPT screens for the three major chromosomal conditions: Trisomy 21 (Down syndrome) Trisomy 18 (Edwards syndrome) Trisomy 13 (Patau syndrome) However, PrenatalSafe uses whole-genome sequencing (WGS) instead of arrays-based analysis, leading to fewer test failures and better performance.
• More Suitable for Early Screening
  Both tests can be performed from 10 weeks of pregnancy, but basic PrenatalSafe NIPT has more stable results due to its advanced sequencing approach. It is ideal for parents seeking reassurance with the most essential trisomy screening.
• More Consistent and Trusted Laboratory
  PrenatalSafe NIPT is processed by Eurofins Genoma, an internationally recognised laboratory known for its rigorous quality control and expertise in prenatal testing. Harmony’s provider (TDL) switched to a different test after discontinuing Harmony due to performance issues, making PrenatalSafe a safer and more established alternative.

Conclusion
For those seeking basic trisomy screening (T21, T18, T13) with greater reliability, basic PrenatalSafe NIPT is a superior alternative to the discontinued Harmony Test. It offers lower no-call rates, more accurate results, and enhanced test stability, making it a trusted choice for expectant parents.

Panorama AI is a good choice for parents who want an extended basic panel available very early in pregnancy. It uses advanced genetic technology combined with an artificial-intelligence (AI) algorithm and can be performed from 9 weeks. Alongside Down’s, Edwards’ and Patau’s syndromes, it screens for DiGeorge syndrome (22q deletion) and triploidy. It also has a low no-call rate of 1.4 per cent and a favourable fetal-fraction cut-off of 2.8 per cent, with the option to add microdeletions screening for an additional fee (+£200).

At London Pregnancy Clinic, Panorama is always paired with an expert early anomaly scan so we can confirm it is suitable for you before any blood is taken. Because samples are analysed at a laboratory in the United States, results take around 7–10 working days. If you would prefer a UK-based lab with a faster turnaround, our specialists can compare Panorama with our other options during your consultation and help you decide. For extra reassurance, we also recommend combining NIPT with our 10-week scan.

The Harmony Test was a basic non‐invasive prenatal test that enjoyed popularity in London around 2010, largely thanks to effective marketing. However, it was discontinued in 2023 by its provider in London, The Doctors Lab (TDL), likely due to unsatisfactory performance. Our clinic’s extensive experience has demonstrated that the Harmony Test suffered from poor reliability and a high rate of inconclusive results, and we were rather relieved when it was withdrawn. Many of our patients expressed significant dissatisfaction with their experience of the test. Curiously, however, several clinics in London in 2025 continue to offer a test under the name “Harmony Test.” Our understanding is that they are using the term as a generic reference to a type of NIPT offered by another brand. For screening the same conditions—with markedly improved performance—we strongly recommend PrenatalSafe as a direct replacement for the Harmony Test.

22q deletion (del) syndrome or Di George syndrome is a genetic condition, which is caused by a small, missing or “deleted” piece of the 22nd chromosome. Unfortunately, that missing piece can affect every system in the human body including the heart (heart defects in 75% babies), palate, immune system, hormones, kidneys and others. It also can affect mental health and is associated with learning and behavioural differences, anxiety, and other mental health issues like schizophrenia (in 25% of adults). Panorama NIPT and SMART Test® – KNOVA screen for DiGeorge syndrome. Early detection of 22q del can lead to earlier interventions and better outcomes for affected individuals. For instance, in our clinic, we can perform early fetal echocardiography from 12 weeks to exclude severe heart anomaly associated with 22q del. For more information, please visit www.22q.org

Longer turnaround time: up to 10 working days. This is due to the time taken to transfer the samples to the US based lab. Application of extended diagnostic panels (sex chromosomes, triploidy, 22q del, microdeletions) increase the chances for false positive and inconclusive results. The positive or inconclusive results of the test in some cases do NOT covered by NHS and you may require private genetic counselling and possible private invasive test (CVS or amniocentesis) for your own expense.

The main limitation of the Harmony Test was its reliability. In its later years in London the test had a high no-call rate — around 6 per cent, rising to roughly 33 per cent in 2023 — which meant many parents had to give a repeat blood sample or received no clear result at all. It used an older array-based method and, in our clinic’s experience, showed poorer performance than newer whole-genome sequencing tests. Its provider, TDL, discontinued the test in London in 2023.

Because the original Harmony Test is no longer available, London Pregnancy Clinic recommends PrenatalSafe NIPT as a direct replacement: it screens for the same three conditions (T21, T18 and T13) but with a much lower no-call rate and more stable results. If you were previously offered a Harmony Test elsewhere, our specialists are happy to explain the differences and help you choose the most reliable option for your pregnancy. You can read the full background on our Harmony Test page.

Currently NIPT is not routinely offered by the NHS. The nuchal translucency (NT) thickness measurements scan was developed in the 1990s, and at the time was the best screening option for Down’s syndrome offering about 62% accuracy and a 5% false positive rate. The NHS now offers the ‘combined test’ at 11-14 weeks which includes a nuchal translucency scan along with a blood test (for PAPP-A and HCG proteins) with improved the accuracy of 81% and false positive rate of 4.5%. NIPT was first introduced in 2011 and was shown to have superior accuracy to the combined test with a detection rate above 99% for Down’s syndrome and a false-positive rate below 0.1%. Please note, we still recommend following through with your NHS antenatal appointments, they are important for the continuity of your pregnancy care.

Leading biotechnology companies in NIPT, including Natera (Panorama), Eurofins (PrenatalSafe Complete Plus), and Fulgent (KNOVA)—all offered by London Pregnancy Clinic—have developed commercially available tests to screen for microdeletions (including 22q del), single-gene disorders, and sex chromosome abnormalities. While these tests utilise cutting-edge technology, peer-reviewed validation data remains limited, and the true likelihood of false-positive results is unclear. In the UK, the NHS may view these tests as controversial and could refuse to accept a ‘high probability’ or ‘inconclusive’ result as grounds for referral for invasive testing or NHS genetic counselling. To support you, London Pregnancy Clinic offers complementary genetic counselling and a free targeted expert scan to assess structural features associated with the suspected chromosomal or genetic condition. However, we do not perform private invasive diagnostic tests at our clinic. If you opt for these advanced screening options, we will guide you through the process and refer you to relevant private services if needed. Please note that these services may incur additional costs.

Yes, you can. Panorama AI works from 9 weeks. Please note that in this case, structural assessment of the baby by ultrasound can be limited and we will be unable to screen for some very serious conditions like holoprosencephaly or spina bifida. If you wish to have NIPT before 10 weeks, please consider a scan from 9 weeks 4 days.

Following your ultrasound scan appointment, you will receive a detail scan report from our doctors, as a hard copy and a PDF version sent to you via our secure cloud system Tricefy. As soon as we receive your NIPT test results from the laboratory, our clinician reviews the test results and signs them off. One of our friendly clinical staff will then contact you via a phone call to interpret the test results. We will then send you a soft copy of the test results via Tricefy.

The majority of NIPT are NOT validated and cannot be used in pregnancies with: a history of or active malignancy a pregnancy with triplets, quadruplets or higher order a history of bone marrow or organ transplants mosaicism for the parents maternal aneuploidy (chromosomal abnormality) in women under the age of 18 Please note that IVF pregnancies are eligible for a NIPT

• PrenatalSafe (Basic – T21, T18, T13) → 2-5 working days
• Panorama (Natera) → 7–10 working days
• KNOVA (Fulgent Genetics) → 7–10 working days
• UNITY (Carrier Screening + Fetal Risk Assessment) → up to 28 working days
• PrenatalSafe Complete Plus (Extended NIPT Panel) → up to 28 working days

Several factors may extend the turnaround time (TAT) for NIPT results, including:

• Courier and Sample Transport Delays (very rare)
  Blood samples must be shipped internationally (e.g., to the USA for Panorama and KNOVA, or Italy for PrenatalSafe).
• Batch Processing
  The majority of NIPT labs process samples in batches rather than individually. If a sample arrives just after a batch has been processed, it may need to wait for the next run, adding extra time.
• Quality Control Checks
  Advanced genetic screening requires multiple verification steps to ensure accuracy and reliability.
• Unpredictable Laboratory Overload
  High demand for genetic testing can lead to temporary backlogs. Labs process thousands of samples daily, and unexpected spikes in volume may slow down results.
• Insufficient Fetal Fraction
  If the fetal DNA level in the sample is too low, the lab may need to run a second test (often requiring a second blood tube).
• Additional Testing for Complex Panels
  Extended NIPT (e.g., PrenatalSafe Complete Plus, UNITY) involves screening for genetic syndromes and single-gene disorders, requiring more analysis time.

In rare cases, if a sample is inconclusive, the laboratory may request a repeat blood draw, adding further delay.

The main advantages of NIPT are related to Down’s syndrome (T21) screening. They are: early testing from 10 weeks high negative predictive value for T21 high detection rate for T21 low false-positive rate for T21

As any screening test NIPT has some disadvantages. Here there are the most significant NIPT limitations: relative high cost of the cfDNA test (Harmony Test) whilst a very sensitive screening test, it is not diagnostic cannot detect ANY physical (structural) anomaly very limited effectiveness for the babies that have increased nuchal translucency (NT) thickness or physical (structural) anomaly processing time of up to a week (or longer in 5% of the cases) or even 10 days for Invitae NIPS failure to return a result in up to 5% of women (‘no-call’ results) which is more common for Harmony Test

Currently, we consider PrenatalSafe as the best option for NIPT in London, because it provides advanced technology, low no-call results, and a short turnaround time (the lab is UK based). PrenatalSafe can be considered the best replacement for the outdated Harmony Test. Pros: advanced technology reliable screening for Down’s syndrome uses a small amount of maternal blood short turnaround time low no-call rates works for vanishing twin syndrome highly reputable in Europe Cons: Limited experience using the test in London

The main advantages of the brand-new panorama AI algorithm comparing with other NIPT providers are: £200 test cost. This transparent price solution makes our combination of expert ultrasound scan and NIPT to be the most advanced and cost-effective option for early reassurance of the parents Fewer no-call results (1.4%) than other NIPT providers Low fetal fraction cull-off (only 2.8%) Extended diagnostic panel: option to screen for Di George Syndrome ( 22q del), Turner syndrome, triploidy and other conditions for an additional fee. The main disadvantages of Panorama Test are: Longer turnaround time of 7-10 working days because of blood sample transfer to North America-based Natera Laboratory. Higher chance for false-positive and inconclusive results.

In case the NIPT result shows a high chance for Down syndrome or other conditions, our doctor will contact you and explain the further steps we advise to take. We will most likely arrange a referral to your NHS fetal medicine unit for further counselling and possible diagnostic test such as CVS or amniocentesis. Alternatively, we can refer you to a private fetal medicine consultant (consultation cost is not included in our service). We will also offer early fetal echocardiography for free (regular cost of the examination £340) for all our patients with high chance NIPT for trisomy 21, Di George syndrome, trisomy 18, trisomy 13 and Turner syndrome.

Although our NIPT options are very accurate, some positive high chance for Downs syndrome results are false and the baby does not in fact have trisomy 21. Biological factors with the potential to cause discordance between cfDNA results and the baby’s genetic status include uncommon conditions like confined placental mosaicism, fetal mosaicism, maternal chromosome changes, and the presence of an unrecognised, nonviable (or viable) twin.

Most pregnant women receive complete results from cfDNA testing, indicating either a high or low probability for aneuploidy. In about 3% of cases (much more common with a harmony test) we will need to contact you without giving you a test result and ask you to come in for an additional sample of blood or to give us more information about your pregnancy or medical history. There will be no extra cost for an additional mother’s blood test. It is because in small proportion of blood specimens submitted after 10 weeks gestation there is an insufficient amount of the baby’s cfDNA. This situation is called low fetal fraction. The chance to have low fetal fraction is getting higher with increased maternal body weight. There are other rare factors making NITP results inconclusive. In the case of a harmony test no-call result, we will discuss options of alternative screening and/or referral for diagnostic testing if you either decline a second attempt at NIPT or do not receive a result after two attempts.

The harmony scan can only be done from a gestational age of 10 weeks, while panorama NIPT can be done from 9 weeks. TDL/Natera do not accept any blood samples for patients below that gestational age. We recommend waiting until a gestational age of 10 weeks + 2 days (9+4 for panorama) to perform the harmony/panorama scan to avoid having to come in more than once.

In case you booked for a panorama/harmony scan, but the ultrasound scan indicated a GA below 9/10 weeks (respectively), we will have to rearrange for you to come in at a later date for an additional cost of £50 to cover for our staffing cost.

In the case of no-call results from the test (about 3% of the cases), we will be happy to schedule in another time to draw another blood sample free of charge. In case of a second no-call result, we will refund the harmony test portion of the appointment charge as per below.

If, upon discussion with our clinician, you decide that the harmony test is not the right decision for you, we will refund the harmony test proportion of the appointment and will only charge for the scan.

In the case of inconclusive results for Downs syndrome or trisomies 18 or 13, we are committed to refunding the harmony test cost. Because the harmony test is being undertaken by a third party, TDL (The Doctors Laboratory), we will contact them to arrange the refund. The refund will be for the harmony test only (we cannot compensate the cost of ultrasound) and will be processed in a few business days.

There is no reimbursement for inconclusive fetal sex results. In those rare cases we will offer you an anatomy and gender scan for a reduced cost and will discuss the findings and need for further referrals.

No, we think it is outdated approach and the best way is to perform both the 10 week anomaly scan and NIPT at 9-10-11 weeks. The benefit of this approach is that the tests are performed as early as technically possible. Understandably it will be impossible to visualise some fetal structures and organs at 10 weeks and some structural anomalies will be undiagnosed at this very early stage. Keeping this in mind, we recommend performing our early fetal scan at 15-16 weeks for further reassurance and exclusion of majority severe structural anomalies. Learn more about our early pregnancy scans.

Vanishing twin is a situation with twin pregnancies when the embryo or fetus in one of the sacs fails to develop or dies at the early stages of pregnancy. Interpretation of NIPT in the case of a vanishing twin phenomenon is complicated due to contamination of the sample by DNA of a non-developing twin pregnancy. Our advanced NIPT: PrenatalSafe Complete Plus can be used in this situation. NIPT should be performed at least 5 weeks after a vanishing twin has been diagnosed on ultrasound, to reduce the risk of inaccurate results. This waiting period is crucial because the cfDNA (cell-free DNA) from the demised twin can remain in the mother’s bloodstream and may interfere with the results. Testing too early can lead to inaccurate or falsely high-risk results.

During September 2023, The Doctor’s Laboratory (TDL Genetics) who had the exclusive rights for performing the Harmony Test NIPT in the UK, announced that it had ceased offering the test. As an alternative, the laboratory opted to offer VeriSeq™ NIPT Solution v2, which has been used by other laboratories in the UK for a couple of years. At London Pregnancy Clinic, we chose to use PrenatalSafe, which uses the same apparatus as Illumina’s NIPT test but has a better algorithm, validation data, and more experience with the technology.

Learn more about Illumina NIPT

Yes. Through our trusted partner Jeen Health, you can book an at-home NIPT test from anywhere in the UK. Before your test, their team of specialists will carefully review your pregnancy scan to confirm that NIPT is suitable for you. This ensures your results are as accurate and meaningful as possible. You’ll also have a 20-minute online consultation with a genetic counsellor, who will guide you through the available test options and answer your questions. In more complex pregnancies (such as IVF, twin pregnancies, or vanishing twin), Jeen’s clinical team provides the expert guidance you need to make an informed choice. Blood collection is flexible: You can arrange your own local blood draw, Attend our clinic in London (city or west), or Book a home phlebotomy visit anywhere in the UK (+£65). Your test kit is sent with next-day delivery, and results are shared securely online. If you are over 17 weeks pregnant, Jeen’s clinical team will review your case before confirming which test can be offered. This means whether you’re in Manchester, Edinburgh, or anywhere else in the UK, you can still access advanced NIPT testing with the reassurance of Jeen Health.

Not through London Pregnancy Clinic — every NIPT we offer includes an expert ultrasound scan. The scan confirms your pregnancy is viable, dates it accurately and checks it is suitable for testing, which is why we do not offer the blood test on its own.

If you cannot get to our London clinic, our partner Jeen Health offers NIPT across the UK, with the same laboratories behind several of our tests. You will need to provide proof of a pregnancy scan taken within the last 7 days before your blood sample is taken.