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 stuff 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.

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 world’s most advanced screening packages
• KNOVA NIPT provided by Fulgent Genetics, a leader in genetic syndromes
• It screens for about 100 anomalies and syndromes
• Its curated panel reduces false positives
• It uses cutting-edge genetic technology
• Its turnaround time is similar to Panorama (7-10 working days)
• It yields fewer than 1.5% no-call results

Please refer to pages 8–10 for an example of a comprehensive KNOVA NIPT report, including detailed performance statistics.

• Advanced genetic technology
• Whole-Genome Sequencing (WGS)
• Proved performance for Down’s syndrome screening
• Less no-call results (<2%)
• Fast results: 3-5 working days

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.

• Advanced genetic and artificial intelligence (AI) technology
• Available from 9 weeks
• Di George Syndrome (22q del) screening
• Triplody screening
• Less no call results (1.4%)
• Better fetal fraction cutoff (2.8%)
• Option of additional microdeletions screening (for an additional fee +200)

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.

Unfortunately Harmony in London in the last few years had many limitations, which have prompted its provider TDL to terminate its performance.

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 99.99% detection rate and sub 0.1% false negatives. 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.

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. 

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

Processing Time for NIPT Blood Tests

• 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

Please refer to the following Q&A section, which explains why the turnaround time (TAT) may occasionally be longer than expected.

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 £320) 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.

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 can be used in this situation.

Delaying the NIPT by five weeks is a recommended approach to reduce the chances of false-positive results associated with the vanishing twin syndrome.

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.