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            [slug] => gentis-dao-tao-chuyen-sau-ve-ky-thuat-pgt-tai-bv-san-nhi-quang-ninh
            [title] => GENTIS provides intensive training in PGT techniques at Quang Ninh Obstetrics and Gynecology Hospital
            [description] => On February 28, at Quang Ninh Obstetrics and Gynecology Hospital, GENTIS company held a seminar to train and update information on genetic analysis techniques before PGT embryo transfer for the team of doctors at the Hospital assisted reproduction department.

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Updating new knowledge on genetic analysis and testing services is a cross-cutting activity of GENTIS in the process of supporting partners and customers to deploy the service effectively. Accordingly, GENTIS held a presentation seminar on the topic "Pre-embryo Transfer Genetic Screening (PGT)" at Quang Ninh Obstetrics and Children's Hospital on February 28.
The seminar was attended by nearly 15 doctors and nurses from the hospital leadership, reproductive support department and laboratories. Especially, there were the presence of Deputy Director of the hospital Dr. CKII Do Duy Long, Head of IVF lab Dr. Vu Thu Hang, Head of genetics lab Dr. Ngo Kim Ngan and Head of Nursing Department of HTSS Dr. Nguyen Thi Lien and other techniques staff working in the hospital laboratory.
GENTIS Company was honored to have the participation of the Director of the Testing Center - MSc. Nguyen Quang Vinh is a direct report on PGT services and Mr. Pham Cao Khai - GENTIS test team leader helps guide how to store and send PGT samples from the hospital.
At the beginning of the report, Director Nguyen Quang Vinh shared preliminary about genetic analysis test before embryo transfer with 3 types: PGT-A, PGT-SR and PGT-M, in which the report focuses on data’s research practice at GENTIS. Currently, all babies are born with a probability of having an abnormal number of chromosomes (chromosome), structural abnormalities or having some genetic diseases.
Therefore, with the ability to analyze 24 chromosome number abnormalities of blastomeres and identify very small (>5mb) deletions/additions, the PGT test will help doctors select embryos with high quality. The best, healthy amount is transferred into the mother's uterus during IVF.

Sharing more details on this topic, Master Vinh said, the rate of chromosomal abnormalities in embryos cultured in vitro can be up to 60% and this is closely related to failed implantation and miscarriage at a high rate. Based on the data collected at GENTIS, the Director of GENTIS Center presented data with the percentage of samples with 24 chromosome abnormalities accounting for 48%, the percentage of samples with no abnormalities detected at 50% and the percentage of samples with abnormality of 24 chromosomes. Unanalyzed noise accounted for 2%.
Through research, mutations occurring on many different chromosomes (except for the case of Y chromosome) in day 3 embryos are quite similar, but this rate in day 5 embryos is quite different. Usually small chromosomes have a greater rate of abnormalities (13,15,16,18,21,22). This could be explained by the fact that embryos carrying abnormally large chromosomes have a lower growth rate to day 5.
Emphasizing at the training session, Ms. Vinh focuses on the significance and application of PGT-M test - pre-embryo transfer genetic test for single-gene diseases, indicated for couples carrying genetic abnormalities.
To date, GENTIS has performed routine PGT-M testing in hospitals and detected more than 30 genetic disease syndromes. Not only common diseases such as Thalassemia, muscular atrophy, hemophilia... but other rare and dangerous genetic diseases are also performed by GENTIS experts such as Wilson's disease, Pompe syndrome, cystic fibrosis, Fabry's disease, etc. , congenital hearing loss, congenital hypothyroidism, Smith-Lemli-Opitz syndrome, vitreous bone disease, autosomal dominant polycystic kidney...
The director of GENTIS Center also shared that, in addition to the diseases on the routine list, GENTIS can perform PGT-M for most diseases and genes, including new diseases that have not yet been performed by any unit in Vietnam. In these cases, the hospital needs to provide information about the mutation to be performed, the genetic test results in the parents first, so that GENTIS can give appropriate advice.

During the training session, Master Vinh also raised the issue of the abnormal detection range in PGT-A/SR, which can only detect microdeletions/repetitions: >5 Mb (Veriseq PGS kit, illumina) , >8 Mb (Reproseq, Thermofisher) and >7 Mb (PGSeq, PerkinElmer). That's why the research and development team of GENTIS experts should test PGT MAX 1 with higher resolution, detect deletions/repetitions as small as 2Mb and find out the causes affect embryo transfer.
Some dangerous syndromes with a cumulative rate of nearly equal to Down, Edward, and Patau syndromes such as: common genetic syndromes/diseases such as deletion 22q11.2 (Digeorge syndrome), deletion 1p36 (Loss syndrome) segment 1p36), deletion 15q11.2 (Prader Willi/Angelman syndrome).
With Veriseq PGS technology and the new generation DNA sequencing system NGS of Illumina - USA deployed at GENTIS, the PGT test has:
- High resolution with more than 3,000 data points (probes) to help screen for abnormalities of all 24 chromosomes.
- Number of reads up to 1,000,000 reads/sample. Can detect loss and add fragments > 5Mb in size.
- 99.99% sensitivity; The specificity is 99.98%.
Bluefuse analysis software identifies more than 130 syndromes associated with chromosomal deletions and deletions

At the end of the seminar, GENTIS discussed with the laboratory team of Quang Ninh Obstetrics and Children's Hospital about the issues that need to be coordinated in the embryo delivery and receipt process. Doctors at the hospital had a lively discussion about how to preserve samples, collect samples, return samples, and how to access the service to be suitable for pregnant women with multiple miscarriages and couples. Husband performed in vitro fertilization.
The GENTIS test team leader noted that the Hospital should use the kits and canisters provided by GENTIS to ensure the best biopsy quality. The kit GENTIS uses ensures anti-adhesion of cells inside the tube wall, keeping the embryo transfer medium and blastomeres always at the bottom, not on the tube wall. Units that choose GENTIS's PGT service will be supported with the most suitable tools, embryo transfer environment and embryo transfer options to ensure accuracy and time to return results to customers.
Through this update and knowledge sharing session, the doctors of Quang Ninh Obstetrics and Gynecology Hospital had more useful information about genetic screening methods before embryo transfer, screening and washing procedures and embryo transfer after embryo transfer. biopsy to perform the most accurate PGT technique for the patient. To meet the needs of hospitals in general and infertile families in particular, GENTIS will always try to develop and improve more technologies to increase the chances of a healthy and safe pregnancy for people Vietnamese.
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            [slug] => gentis-tiep-tuc-don-nhan-chung-nhan-he-thong-quan-ly-chat-luong-iso-134852016
            [title] => GENTIS is pleased to receive ISO 13485:2016 Quality Management System Certification
            [description] => After the ISO 9001:2015 certification, GENTIS is pleased to continue to receive the ISO 14385:2016 quality management system certificate on November 8, 2022.

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ISO 13485:2016 is a management system standard applied in the field of manufacturing and trading in medical instruments and supplies. With ISO 9001 as its foundation, the importance of continuous improvement is replaced by meeting statutory and customer-specific requirements, managing risk, and maintaining efficient processes, namely the design, manufacture and safe distribution of medical devices.
After more than 12 years of operation, GENTIS achieved ISO 9001:2015 certification for genetic testing and genetic analysis services in 2015, then in 2019, GENTIS achieved ISO 15189:2012 certification for services. GenEva prenatal test. And until most recently, on February 1, 2023, GENTIS was officially granted the ISO 9001: 2015 certificate at both Hanoi and Ho Chi Minh facilities after a period of rigorous assessment and inspection.
However, it does not stop there, GENTIS is very pleased to have also obtained the quality management system certification for the field of medical equipment since November 8, 2022.
All as an affirmation in maintaining the service quality as well as the reputation of GENTIS in the domestic and international markets.

As a companion in GENTIS's ISO standardization stages, Ms. Pham Thi Thuy (GENTIS Quality Management Specialist) said: “Achieving ISO 13485:2016 is proof of our satisfaction. harmonize quality management system requirements with regulatory requirements for the medical device industry. This is an important standard, a must have in the current period if GENTIS wants its products and services to be widely recognized around the world.”



Accordingly, the ISO 13485:2016 standard brings practical benefits not only to businesses but also to customers, such as:
• Activities are managed according to the system, helping to control product quality and safety
• Improve the ability to meet customer requirements. Meet national and international regulations for medical products
• Improve the efficiency of the current management system. Convenient in integration with other management systems.
In the future, GENTIS promises to constantly develop and expand in the international arena, bringing the best products, services and experiences to customers, fulfilling the mission of improving the physical and mental health of Vietnamese people.
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            [title] => Dịch vụ chất lượng cao NIPT tại GENTIS - Trải nghiệm mới cho các mẹ bầu
            [description] => Xét nghiệm sàng lọc trước sinh không xâm lấn GenEva (NIPT - Illumina) của GENTIS là xét nghiệm sàng lọc có độ chính xác cao, giúp hạn chế số thai phụ phải thực hiện các xét nghiệm xâm lấn gây nhiều rủi ro. Đây là xét nghiệm được nhiều bác sĩ sản khoa khuyến cáo các mẹ bầu nên thực hiện.
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Trên thực tế thống kê cho thấy, nước ta có khoảng 1,5-2% trẻ em sinh ra mỗi năm bị mắc dị tật bẩm sinh. Nếu không thực hiện sàng lọc trước sinh, các mẹ không thể chắc chắn rằng con mình có phát triển bình thường kể cả khi bé được hạ sinh an toàn.
Các xét nghiệm thường được nhiều thai phụ biết đến như Double test hay Triple test có độ chính xác dưới 90%, dẫn đến việc nhiều thai phụ phải chọc ối, gây nguy hiểm cho quá trình mang thai. Sản phụ có nguy cơ cao mắc các tai biến như: sảy thai, thai lưu, nhiễm trùng... sau khi bị chỉ định chọc ối. Việc làm xét nghiệm sàng lọc trước sinh là biện pháp tối ưu giúp giảm thiểu tối đa các nguy cơ kể trên.
 Xét nghiệm sàng lọc trước sinh không xâm lấn GenEva (NIPT - Illumina) là giải pháp an toàn cho các thai phụ, phương pháp này sẽ phân tích các ADN tự do trong máu mẹ ở tuần thai thứ 10 để sàng lọc một số bệnh di truyền phổ biến nhất. Trong suốt quá trình mang thai, một lượng ADN của thai nhi được giải phóng và di chuyển tự do trong máu mẹ, người ta gọi các ADN này là ADN tự do (cfDNA) là cơ sở để sàng lọc chính xác các bất thường liên quan đến NST gây nên các dị tật bẩm sinh.
Theo PGS-TS Vũ Bá Quyết - Nguyên Giám đốc bệnh viện Phụ sản Trung ương, GenEva giúp phát hiện sớm các hội chứng Down, Edwards, Patau, các bất thường nhiễm sắc thể giới tính, đột biến vi mất đoạn và các bất thường số lượng tất cả các nhiễm sắc thể còn lại. Xét nghiệm đảm bảo an toàn và cho kết quả chính xác tới 99,9%.
Cùng là những xét nghiệm không xâm lấn nhưng GenEva có độ chính xác cao hơn các phương pháp sàng lọc truyền thống như Double test, Triple test... giúp giảm thiểu nguy cơ phải thực hiện các xét nghiệm xâm lấn gây nguy hiểm cho thai kỳ. Để thực hiện phương pháp này, mẹ chỉ cần lấy 7ml máu ở tuần thai thứ 10 (theo khuyến cáo của Bộ Y tế) mang đi xét nghiệm đã có thể cho kết quả chính xác chỉ từ 4 ngày làm việc.
GenEva (NIPT - Illumina) được khuyên thực hiện cho tất cả các thai phụ ngay từ tuần thai thứ 10 của thai kỳ, đặc biệt là những thai phụ nằm trong nhóm nguy cơ cao sinh con mắc phải những hội chứng di truyền như: 

 Phụ nữ mang thai trên 30 tuổi, đặc biệt trên 35 tuổi; 
 Có tiền sử sinh con dị tật/ đã từng sảy thai; 
 Các trường hợp từng bị thai lưu với mang thai dị dạng hoặc thai chết lưu không rõ nguyên nhân; 
 Có kết quả siêu âm bất thường; 
 Có kết quả Double test và/hoặc Triple test nguy cơ cao; 
 Có thực hiện kỹ thuật hỗ trợ sinh sản (IVF); 
 Mang thai đôi...

GenEva là xét nghiệm NIPT do hãng Illumina (Mỹ) chuyển giao chính thức cho GENTIS, vì thế chất lượng luôn đáp ứng các tiêu chuẩn quốc tế khắt khe như tại thị trường Mỹ. Thời gian trả kết quả chỉ từ 4 ngày với độ chính xác lên tới 99.9%. Bên cạnh đó, GenEva còn đạt được ISO 15189:2012 về quản lý chất lượng phòng xét nghiệm. 
Ngoài ra, GENTIS có rất nhiều chuyên gia, bác sĩ giàu kinh nghiệm trong lĩnh vực di truyền kết hợp với các bác sĩ sản khoa uy tín trên cả nước, đội ngũ tư vấn được đào tạo chuyên sâu, nhiệt tình và tận tâm. Khi đăng ký làm xét nghiệm sàng lọc trước sinh GenEva tại GENTIS, mẹ bầu sẽ được trải nghiệm dịch vụ chuyên nghiệp, tiện ích như:

 Đăng ký lấy máu xét nghiệm NIPT ngay tại nhà, giúp mẹ hoàn toàn an tâm, tránh rủi ro và tiết kiệm được chi phí.
 Chủ động đăng ký xét nghiệm với thao tác dễ dàng qua tổng đài miễn phí 1800 2010.
 Mẹ bầu thoải mái lựa chọn thời gian xét nghiệm, phù hợp với lịch cá nhân của mẹ bởi Trung tâm làm việc tất cả các ngày trong tuần.

Cha mẹ hãy thực hiện xét nghiệm sàng lọc trước sinh GenEva (NIPT - Illumina) cho bé ngay từ trong bụng mẹ để có thể an tâm và mang lại cho bé yêu sự khởi đầu trọn vẹn nhé !
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            [title] => GENTIS tiên phong trong dịch vụ xét nghiệm NIPT 
            [description] => Từ tháng 03/2019,  GENTIS là một trong những phòng xét nghiệm hiếm hoi trên toàn quốc đạt được chứng chỉ ISO 15189:2012 cho dịch vụ xét nghiệm trước sinh GenEva (illumina's NIPT).
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Sàng lọc trước sinh không xâm lấn NIPT là phương pháp phân tích ADN tự do của thai nhi có trong máu mẹ để phát hiện những rối loạn di truyền mà thai nhi có thể mắc phải do đột biến số lượng hoặc cấu trúc nhiễm sắc thể. 
NIPT thường được sử dụng để tìm kiếm các rối loạn nhiễm sắc thể gây ra bởi sự thừa hoặc thiếu một bản sao của nhiễm sắc thể. NIPT chủ yếu chẩn đoán thai nhi mắc các hội chứng sau;

Hội chứng Down (trisomy 21, gây ra bởi nhiễm sắc thể 21 )
Trisomy 18 (gây ra bởi nhiễm sắc thể 18 )
Trisomy 13 (gây ra bởi nhiễm sắc thể 13 )
Thêm hoặc thiếu các bản sao của nhiễm sắc thể X và Nhiễm sắc thể Y (nhiễm sắc thể giới tính). 

Nghiên cứu cho thấy xét nghiệm NIPT có độ chính xác >99%, cao hơn hẳn double test và triple test, đặc biệt có độ nhạy cao với ba thể tam nhiễm: hội chứng Down, hội chứng Patau, hội chứng Edwards. Đặc biệt, NIPT được coi là không xâm lấn vì chỉ cần lấy 7ml máu từ người mẹ và không gây nguy hiểm cho thai nhi. Xét nghiệm được thực hiện khi mang thai ở tuần thứ 10. 
Tại Hà Nội, Công ty GENTIS là một trong những đơn vị tiên phong triển khai xét nghiệm sàng lọc trước sinh không xâm lấn NIPT. GenEva là xét nghiệm NIPT do hãng Illumina (Mỹ) chuyển giao chính thức cho GENTIS, vì thế chất lượng luôn đáp ứng các tiêu chuẩn quốc tế khắt khe như tại thị trường Mỹ. Thời gian trả kết quả chỉ từ 4 ngày với độ chính xác cao nhất. Bên cạnh đó, GenEva còn đạt được ISO 15189:2012 về quản lý chất lượng phòng xét nghiệm. 
Có thể nói, GENTIS là đơn vị y tế uy tín cung cấp các dịch vụ liên quan tới giải trình tự gen tại Việt Nam. GENTIS sở hữu 2 phòng xét nghiệm hiện đại hàng đầu châu Á ở cả Hà Nội và TP. Hồ Chí Minh, được kiểm định và công nhận bởi FDA – Tổ chức đánh giá uy tín tại Mỹ.
GENTIS sở hữu hệ thống máy móc xét nghiệm tiên tiến, hiện đại, liên tục cập nhật những xu hướng điều trị mới nhất trong nước và ngoài nước, luôn luôn phát triển vì sứ mệnh nâng cao thể chất và trí tuệ người Việt.
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            [title] => GENTIS tri ân 68 năm ngày Thầy thuốc Việt Nam 
            [description] => Y đức là phẩm chất tốt đẹp của người làm công tác y tế, được biểu hiện ở tinh thần trách nhiệm cao, tận tụy phục vụ, hết lòng thương yêu chǎm sóc người bệnh, coi họ đau đớn như mình đau đớn, như lời Chủ tịch Hồ Chí Minh đã dạy: “Lương y phải như từ mẫu”.
            [content] => 
Hằng năm cứ đến ngày 27/02 là mọi người dân Việt nam lại có dịp được thể hiện lòng kính trọng và sự biết ơn của mình đến các y – bác sĩ.
Ngày 27/02 là ngày Thầy thuốc Việt Nam, bắt đầu từ sau năm 1955, gắn với sự kiện Chủ tịch Hồ Chí Minh viết thư gửi Hội nghị cán bộ ngành y tế. Bộ Y tế Việt Nam đã lấy ngày 27 tháng 2 làm ngày truyền thống của ngành nhằm nêu cao trách nhiệm và tài trí của người cán bộ y tế trong sự nghiệp xây dựng và bảo vệ Tổ quốc. 

Trong 67 năm qua Ngành Y tế đất nước ta đã có bước phát triển toàn diện, mạnh mẽ. Mạng lưới y tế dự phòng, cơ sở khám chữa bệnh, sản xuất và cung ứng dược phẩm; hệ thống chính sách tài chính, bảo hiểm y tế; năng lực chuyên môn, trình độ khoa học của đội ngũ y bác sĩ, cán bộ nghiên cứu về sức khỏe… đều có bước phát triển vững mạnh. Nhiều giáo sư, bác sĩ đã được nhà nước vinh danh phong tặng Anh hùng lực lượng vũ trang nhân dân, Anh hùng lao động, Thầy thuốc nhân dân, Thầy thuốc ưu tú. Đó là những tấm gương sáng về đạo đức, tinh thần vì nước, vì dân, sống hết mình vì người bệnh, xứng đáng là tấm gương sáng để các thế hệ sau noi theo và phát huy để phục vụ tốt hơn nữa trong công tác chăm sóc và bảo vệ sức khỏe cho nhân dân.
Ngoài sự tận tụy với công việc, bệnh nhân còn là những gian khổ khi phải xa gia đình, người thân kéo dài, làm việc dài ngày trong môi trường lây nhiễm và căng thẳng, nhưng những khó khăn, nguy hiểm đó đều không cản trở được tinh thần của người thầy thuốc. Áp lực, vất vả là thế nhưng không làm giảm đi ý chí của họ. Đó không chỉ là nghĩa vụ với nghề, mà còn là trách nhiệm công dân khi Tổ quốc cần, là nghĩa đồng bào, là tình đồng chí cao cả.
Ngày Thầy thuốc Việt Nam không chỉ là ngày tôn vinh nghề thầy thuốc, mà còn là ngày nhắc nhở mọi người hãy sẻ chia với những khó khăn của ngành Y tế.
Nhân Ngày Thầy Thuốc Việt Nam 27/2, GENTIS xin kính chúc tất cả những người thầy, người cô, bác sĩ, y tá… cùng những người đã, đang công tác trong ngành y và những người đã nghỉ hưu có thật nhiều sức khỏe, hạnh phúc, gặt hái được thật nhiều thành công trong sự nghiệp, cuộc sống.
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            [title] => Low fetal fraction (FF) leads to inconclusive NIPT test results
            [description] => In the NIPT test, the fetal fraction (FF) is considered the first and important factor to evaluate the test quality. How a low fetal fraction (FF) can lead to indeterminate results in the NIPT test
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I. EFFECT OF Fetal Fraction (FF) on NIPT RESULTS
Non-invasive prenatal screening test (NIPT) is an advanced screening method to detect fetal aneuploidy through fetal free DNA (cfDNA) in maternal blood. Fetal cfDNA is derived from apoptosis of trophoblastic cells (syncytiotrophoblasts), while maternal hematopoietic cells are the source of most maternal cfDNA. Both the mother and the fetal placenta produce cfDNA and circulate in the maternal blood circulation, of which maternal cfDNA accounts for 90% (Figure 1).

In the NIPT test, the fetal fraction (FF) is considered an important factor and is the first factor to evaluate the quality of the test. FF is the ratio of fetal cfDNA to all circulating cfDNA in maternal plasma. As reported by Scheffer et al. 2021, the minimum FF to produce reliable results and minimize the number of false negatives as well as not giving results is 4%. However, for many modern methods used today, reliable results can be obtained at much lower FF levels (from 2.6% - 3.5%).  
According to the 2020 meta-analysis data, between 1.7 and 8% of pregnant women with very limited amount of fetal DNA circulating in the blood have been reported in clinical cases. In these cases, the amount of cfDNA in the fetus is not enough to read the NIPT result, called "unreportable" or "inconclusive", at which point the pregnant woman is usually advised to have her blood drawn and retest. This causes inconvenience or even anxiety for pregnant women, and increases the cost of sequencing and labor for laboratories.
Low FF was investigated to find out the factors that can influence with the desire to minimize this situation to improve the value of the test. The factors associated with low fetal fractions are known: gestational age, maternal obesity, and technical problems.
II. SOME FACTORS THAT CAN CAUSE NIPT RESULTS
1. Gestational age
From the 5th week of gestation, fetal cfDNA was detectable in the mother's blood, but the amount was too low to warrant NIPT testing. From 10 to 21 weeks of gestation, FF fluctuated around 10-15%, in which fetal cfDNA increased by 0.1% per week (p<0.0001). After 21 weeks of gestation, fetal cfDNA increased by 1% per week (p<0.0001). Therefore, the recommended gestational week to perform NIPT is from the 10th week, accordingly, blood samples taken at an earlier gestational week may cause the FF to be insufficient to ensure the accuracy of the test.
Results from recent studies have shown a correlation between fetal cfDNA levels and gestational age, with FF being proportional to gestational age. In the 2020 study by Danielius et al., the team performed a retrospective study of nearly 1,000 NIPT samples, the results showed that fetal cfDNA levels gradually increased over the weeks of gestation, from 10 to 21 weeks of gestation. , FF fluctuates in the range of 10-15% (Figure 2).
Therefore, the NIPT test should only be performed between 10 and 20 weeks of pregnancy, when the cfDNA concentration is sufficient to ensure the most accurate test results as well as full consultation from the doctor.

2. Maternal obesity
Among the factors that can influence FF, a high maternal body mass index (BMI) is a well-recognized factor. Studies indicate an inverse relationship between BMI and FF to explain inconclusive NIPT results. The reason is explained that in pregnant women with obesity, total cfDNA levels are increased due to increased adipose tissue necrosis and increased apoptosis of vascular stromal cells. Although fetal cfDNA was unaffected, maternal total cfDNA was increased, resulting in a lower overall FF.
The study of Danielius et al in 2020 evaluated the correlation between maternal weight and FF (r = −0.330, p < 0.001). The results showed that the group of pregnant women weighing ≥95 kg had the lowest FF (5.6%), much lower than the group of pregnant women weighing 45-54 kg (FF was 11.1%). (Figure 2).

In addition, some factors such as maternal cancer or autoimmune disease have also been reported to affect FF, since the use of drugs to treat the disease increases the number of total DNA fragments. maternal circulation, resulting in lower FF.
3. Technical problems
Technical issues such as cfDNA extraction efficiency, library generation efficiency and genetic sequencing technology platform are factors that contribute to the success of the assay. Through the DNA extraction process, if the technique is not guaranteed, it can reduce the concentration of cfDNA in the plasma, thereby affecting the quality of gene library creation and the number of copies of sequenced DNA.
Up to now, major research centers around the world are always trying to find and come up with new technological solutions to overcome the risks that cause NIPT results to go unreported, such as improving the extraction efficiency of cfDNA. , optimize the FF to the minimum that can perform the test or set up a dedicated bioinformatics software to analyze the results.
As a pioneer in genetic analysis in Vietnam, GENTIS uses next-generation gene sequencing technology on the NextSeq 550 sequencer system of Illumina, USA. Illumina is known as a leading technology company in the world in gene sequencing, with outstanding quality voted by the worldwide community of scientists as a technology company used in scientific research, develops tests in the field of molecular biology the most.
When comparing Illumina's technology platform with some other technology platforms, Illumina shows outstanding advantages in terms of cfDNA detection at low concentrations of 1.4 - 2.7% and test failure rate. (0.1%) lowest among the platforms being used today. In addition, the GENTIS R&D team has successfully developed a proprietary bioinformatics software that optimizes the readability of the results, thereby improving the accuracy of the NIPT test.
The NIPT test is gaining popularity today because of its high accuracy and helps to reduce the risks posed by invasive methods. However, NIPT is still a screening test, so it is essential to understand and fully understand the nature of the test, as well as the possible causes that lead to NIPT cases not determining the results.
Through the article, GENTIS hopes to have provided more useful information on factors affecting low FF, the main cause of underreported results, thereby helping clinicians make informed decisions. receive the most appropriate advice and guidance.
References:
[1] Hu P, Liang D, Chen Y, Lin Y, Qiao F, Li H, et al. An enrichment method to increase cell-free fetal DNA fraction and significantly reduce false negatives and test failures for non-invasive prenatal screening: a feasibility study. J Transl Med 2019;17:124. 29 
[2] Van Opstal D, Srebniak MI, de Vries F, Govaerts LCP, Joosten M, et al. False negative NIPT results: risk figures for chromosomes 13, 18 and 21 based on chorionic villi results in 5967 cases and literature review. PLoS One 2016;11: e0146794.
[3] Scheffer PG, Wirjosoekarto SAM, Becking EC, et al. Association between low fetal fraction in cell-free DNA testing and adverse pregnancy outcome: A systematic review. Prenat Diagn. 2021;41(10):1287-1295. doi:10.1002/pd.6028
[4] Serapinas D, Boreikaitė E, Bartkevičiūtė A, Norvilaitė K, Narbekovas A, Bartkevičienė D. The Level of Free Fetal DNA as Precise Noninvasive Marker for Chromosomal Aneuploidies: First Results from BALTIC Region. Medicina (Kaunas). 2020;56(11):579. Published 2020 Oct 30. doi:10.3390/medicina56110579
[5] White K, Wang Y, Kunz LH, Schmid M. Factors associated with obtaining results on repeat cell-free DNA testing in samples redrawn due to insufficient fetal fraction [published online ahead of print, 2019 Mar 27]. J Matern Fetal Neonatal Med. 2019;1-6. doi:10.1080/14767058.2019.1594190
[6] Du Y, Chen A, Yang R, et al. A proof-of-concept study on the effects of low total cfDNA content and solutions to increase the NIPT trisomy 21 detection rate. J Clin Lab Anal. 2020;34(2):e23035. doi:10.1002/jcla.23035
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            [title] => Interpretation of False Negative results in the NIPT test
            [description] => The accuracy of NIPT is also highly dependent on technical factors and many other biological mechanisms. Let's learn about the risk of causing false negative results in NIPT test in the article below.
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RISK OF WRONG PRIORITY SCREENING RESULTS
Prenatal screening to detect fetal chromosomal abnormalities has become common among pregnant women. The screening methods are known: fetal ultrasound (nochal translucency), maternal serum screening (β-HCG and PAPP-A) with reported detection rates of 60–90% and the false positive rate is 5%.
If the results of this screening test indicate a high risk of chromosomal abnormalities in the fetus, then an invasive diagnostic test such as chorionic villus sampling (CVS) is recommended at 12–13 weeks of gestation or amniocentesis at 15–16 weeks of gestation. While these tests are valuable diagnostic tools because of their high accuracy, they are associated with a 0.5 to 1.0% risk of miscarriage. Since the discovery of placental-derived free-cell DNA (cfDNA) in the blood of pregnant women, this has been seen as a potential avenue for screening for fetal abnormalities with high accuracy. Highly accurate and completely safe for pregnant women and fetuses.

In 2011, the NIPT test entered clinical practice and is considered the most accurate prenatal screening test, with an abnormal detection rate of more than 99% and a low false positive (FP) rate. (<0.1%) and has been recommended by many professional associations around the world such as: International Society of Obstetrics and Gynecology (ISUOG) and American Society of Obstetricians and Gynecologists (ACOG), American Society of Obstetrics and Gynecology International Prenatal Diagnosis (ISPD) and the Royal College of Obstetricians and Gynecologists (RCOG).
However, the accuracy of NIPT is also highly dependent on technical factors and many other biological mechanisms. The CfDNA used in the NIPT assay is released from placental trophoblasts rather than directly from the fetus, and genetic differences between the placenta and the fetus can lead to these results. Inaccuracies, such as false-positive or false-negative results, expose pregnancy management to some risk.
False-Negative RESULTS IN THE NIPT TEST
A false negative result in the NIPT test is interpreted as not detecting abnormalities in the fetus but in fact the fetus has abnormalities on the syndromes screened in NIPT. False negative results in NIPT are rare, but there have been many studies around the world reporting on this case. According to the 2020 statistics, the false negative rate in NIPT can range from 0.02% to 0.26% (Figure 1).

Specific causes that can lead to false-negative results in NIPT have been investigated and reported, and the causes are known to be: presence of fetal mosaicism; low fetal fraction (FF) (due to early sampling, maternal obesity and some technical factors). Learn more about the causes of false-negative results on NIPT and some of the clinical reports.
CAUSE OF False-Negative NIPT TEST
1. Phenomenon of fetal mosaicism
Placental-placental mosaicism is a challenging biological problem and one of the most frequent causes of discrepancies between NIPT and diagnostic test results. Mosaic accounted for about 20% of all causes of inaccurate NIPT results.
Mosaic is the appearance of two or more cell lines carrying different sets of chromosomes in the same individual. The mosaicism that occurs between the placenta and the fetus can distort the results of the NIPT test. In the case of fetal mosaicism, the fetal cells carry abnormal chromosomes but the placenta carries normal chromosomes, therefore, when performing the NIPT test, analysis of cfDNA released from the placenta could not detect abnormal cells of the fetus.
In the study by Yang et al., 2017 reported a clinical case of a false negative NIPT test.

A 32-year-old woman who became pregnant naturally and had no family history of genetic disease. At 15 weeks' gestation, the NIPT test showed a low risk for trisomy 13, 18, and 21. The woman continued to have routine antenatal checkups, and during the third trimester, ultrasound imaging revealed heart’s abnormalities. After being consulted and prescribed by the doctor, the pregnant woman decided to have amniocentesis to do the karyotype, the results showed that two different cell lines appeared in the fetus: 47,XX,+18[61]/46,XX [39]. In the end, the pregnant woman decided to terminate the pregnancy.
After the termination of pregnancy, QF-PCR and karyotype tests were continued at different sites on the placenta and fetal cord blood to determine the exact cause of this deviation. The results showed that the placenta showed a low risk for trisomy 13, 18 and 21, while cord blood and DNA from amniotic fluid cells showed different cell lines of 47,XX,+18. 61]/46,XX[39]. Conclusion: The occurrence of fetal mosaicism leads to false negative NIPT results.
Currently, technical limitations as well as problems on biological basis do not allow accurate determination of mosaic ratio and type of mosaic through NIPT test. However, understanding the risk of falsifying results that may result from the presence of mosaicism, especially in the case of false negatives, will help pregnant women and doctors be more careful in managing pregnancies, such as the third trimester. second and third trimester, through ultrasound to monitor fetal growth as well as other abnormalities that may appear.
2. Low Fetal Fraction (FF)
Fetal fraction (FF) is the ratio of fetal cfDNA to all circulating cfDNA in maternal plasma. The NIPT test is based on the analysis of fetal cfDNA released into the maternal blood circulation, therefore, FF is directly related to the ability to detect fetal chromosomal anomalies. When the amount of fetal cfDNA is too low, resulting in a low FF, then it is possible for NIPT results to be falsely negative or unreadable.
Low FF is responsible for up to 50% of false negatives. Factors that can affect the fetal fraction were also investigated and evaluated, including: sampling at an early stage, maternal obesity, and technical problems with testing. also affect a certain percentage.
2.1. Low FF due to early gestational week sampling
Fetal cfDNA released into the maternal circulation is reported to be detectable from 5 weeks gestation, from 10 to 21 weeks gestation, FF ranges from 10-15%, in which fetal cfDNA increases 0.1% per week (p < 0.0001). After 21 weeks of gestation, fetal cfDNA increased by 1% per week (p < 0.0001). Fetal cfDNA fragments are approximately 150-160 bp in length, smaller than maternal DNA and account for 11-13.4% of the total cfDNA present in maternal blood. Research results show that the amount of cfDNA of the fetus increases with gestational age and will be lost within a few hours after birth.

A summary report on the rate of FF to ensure the quality of NIPT testing is FF ~ 4%, and the recommended gestational week is from the 10th week of pregnancy. Therefore, when performing maternal blood sampling at gestational weeks earlier than 10 weeks, may result in insufficient fetal cfDNA to read results or lead to inaccurate results.
In the world, the Fertility Associations have also given very specific guidelines on the use of NIPT, NIPT is recommended to be performed from the 10th week of pregnancy and in Vietnam, according to Decision 1807 issued 2020 clearly states: "The recommended week of pregnancy for NIPT testing is from 10 weeks, after having fetal ultrasound results and consulting a genetic counselor for appropriate indications".
2.2. Maternal obesity
In the 2013 study by Wang et al., the team found a correlation between maternal body mass index (BMI) and total cfDNA. In thin pregnant women, total cfDNA concentrations were shown to decrease due to the dilution effect of increased plasma volume. In contrast, in obese pregnant women, total cfDNA levels were increased due to increased adipose tissue necrosis and increased vascular stromal cell death, which offset the dilution effect. Although fetal cfDNA was not affected, increased maternal total cfDNA resulted in lower FF overall (Table 1).
An increase in maternal body weight or BMI may increase maternal circulating cfDNA concentrations leading to a lower FF ratio. After explaining this phenomenon, many researchers have conducted many regression analyzes to quantify the ratio of FF and BMI in mothers, thereby eliminating the association bias caused by gestational age and BMI.

2.3. Technical problems
 In addition to the above main reasons, technical issues such as cfDNA extraction technology, library creation and sequencing, and bioinformatics software reading results are also a factor affecting the accuracy of the results. Up to now, scientists and research centers around the world have always made great efforts to overcome the erroneous rates of NIPT results through the application of new technologies and their incorporation into clinical practice.
NIPT testing at GENTIS uses next-generation sequencing technology on the NextSeq 550 sequencer system of Illumina, USA. Illumina is a leading technology company in the world in gene sequencing, with outstanding quality voted by the worldwide community of scientists as a technology company used in scientific research, pathology, develops tests in the field of molecular biology the most.

When comparing Illumina's technology platform with some other technology platforms, Illumina shows outstanding advantages in terms of cfDNA detection at low concentrations of 1.4 - 2.7% and test failure rate. (0.1%) is the lowest among the platforms being used today (Table 1). In addition, the GENTIS R&D team has successfully developed a proprietary bioinformatics software that optimizes the readability of the results, thereby improving the accuracy of the NIPT test.

Understanding the causes of unsatisfactory NIPT results is essential for clinicians and genetic counselors to comprehensively advise pregnant women and make appropriate indications both before and after performing the test. Along with choosing a reputable testing unit, using the most advanced and modern technology, it will help doctors and pregnant women get accurate results and clearest advice for more peace of mind. pregnancy management.
References: 
[1] Salomon LJ, Sotiriadis A, Wulff CB, Odibo A, Akolekar R. Risk of miscarriage following amniocentesis or chorionic villus sampling: systematic review of literature and updated meta-analysis. Ultrasound Obstet Gynecol. (2019) 54:442–51. 10.1002/uog.20353
[2] Grati FR, Grimi B, Frascoli G, Meco A.M. Di, Liuti R, Milani S, et al. Confirmation of mosaicism and uniparental disomy in amniocytes, after detection of mosaic chromosome abnormalities in chorionic villi. Eur J Hum Genet. (2006) 14:282–8. 10.1038/sj.ejhg.5201564
[3] Mackie F. L., Hemming K., Allen S., Morris R. K., Kilby M. D. (2017). The accuracy of cell-free fetal DNA-based non-invasive prenatal testing in singleton pregnancies: A systematic review and bivariate meta-analysis. BJOG 124, 32–46. 10.1111/1471-0528.14050
[4] Van Opstal, Diane et al. “False Negative NIPT Results: Risk Figures for Chromosomes 13, 18 and 21 Based on Chorionic Villi Results in 5967 Cases and Literature Review.” PloS one vol. 11,1 e0146794. 15 Jan. 2016, doi:10.1371/journal.pone.0146794
[5] Deng C, Liu S. Factors Affecting the Fetal Fraction in Noninvasive Prenatal Screening: A Review. Front Pediatr. 2022;10:812781. Published 2022 Jan 27. doi:10.3389/fped.2022.812781
[6] Wang E, Batey A, Struble C, Musci T, Song K, Oliphant A. Gestational age and maternal weight effects on fetal cell-free DNA in maternal plasma. Prenat Diagn. 2013;33(7):662-666. doi:10.1002/pd.4119
[7] Yang J, Qi Y, Guo F, et al. A case of placental trisomy 18 mosaicism causing a false negative NIPT result. Mol Cytogenet. 2017;10:40. Published 2017 Oct 27. doi:10.1186/s13039-017-0341-5
[8] Vora, Neeta L et al. “A multifactorial relationship exists between total circulating cell-free DNA levels and maternal BMI.” Prenatal diagnosis vol. 32,9 (2012): 912-4. doi:10.1002/pd.3919
[9] Samura, Osamu, and Aikou Okamoto. “Causes of aberrant non-invasive prenatal testing for aneuploidy: A systematic review.” Taiwanese journal of obstetrics & gynecology vol. 59,1 (2020): 16-20. doi:10.1016/j.tjog.2019.11.003
[10] Illumina. Analytical Validation of the verifi® prenatal test: Enhanced Test Performance for Detecting Trisomies 21, 18, and 13 and the Option for Classification of Sex Chromosome Status. Illumina White Paper. 2012.
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            [created_time] => 2023-02-22 11:10:13
            [updated_time] => 2023-08-23 15:07:05
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            [created_by] => 63
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            [language_code] => en
            [slug] => nguyen-nhan-gay-nen-ket-qua-duong-tinh-gia-trong-xet-nghiem-nipt
            [title] => Explain the cause of false positive results in NIPT test
            [description] => Cases of discrepancy between NIPT results and diagnosis, although few, have been reported by many research groups. Among them, a more common case is the false-positive NIPT result. Learn more about what causes false-positive results in the NIPT test below.
            [content] => 
False POSITIVE IN NIPT TEST
Non-invasive prenatal screening test (NIPT) helps to screen for common fetal malformations through the analysis of fetal cfDNA released into the mother's blood with high accuracy and absolute safety. Figure 1). The NIPT test has been shown to be clinically effective with more than 99% accuracy, as evidenced by the increasing use of NIPT over the past decade and has become an indispensable prenatal screening test in clinical practice in many countries around the world.

The advent and rapid advancement of next-generation sequencing (NGS) technologies have increased the accuracy of the method. However, NIPT remains a screening test, and if the results are high-risk, confirm the results with an invasive diagnostic test. There are many factors that affect the accuracy of the NIPT test, including biological factors.
Cases of discrepancy between NIPT results and diagnosis, although few, have been reported by many research groups. Among them, a more common case is the false-positive NIPT result. Based on multiple meta-analyses, reported false positive rates range from 0.04% to 0.06% for trisomy 21, 18, and 13. Factors causing false positives in the NIPT test are known to be: placental mosaicism, abortive twin pregnancy, maternal malignancy, and maternal chromosomal mosaicism.
CAUSE OF False POSITIVE RESULTS IN NIPT TEST
1. Placenta mosaic
Mosaic is the presence of two or more cell lines with different sets of chromosomes in the same individual. Mosaic phenomenon accounts for about 1-2% in natural pregnancies and according to incomplete statistics, is higher in cases of assisted reproduction. However, mosaic accounts for up to 20% of cases where NIPT results and invasive diagnostic results are inconsistent.
In the case of placental mosaicism, also known as localized placental mosaicism, the placenta appears many abnormal cell lines with different chromosomes, while the fetus has a completely normal set of chromosomes. At this time, the NIPT test based on the analysis of cfDNA released from the placenta will give a positive NIPT result, but in fact the fetus is completely healthy. In this case, mosaic caused a false-positive NIPT result.
Reports have also highlighted a few cases of placental mosaicism that resulted in false-positive NIPT results. In the study of Agnese et al in 2022, the research team reported a case of a pregnant woman at 15 + 3 days of gestation who was advised to perform NIPT test, NIPT results showed a high risk of T21 with z-score. is 16.21.
To confirm a positive NIPT result, at 19 + 2 days of gestation, the pregnant woman conducts amniocentesis to perform QF-PCR and karyotype, the results do not detect abnormalities on chromosome 21. With this result, the pregnant woman was carefully consulted and explained by the doctor about the discrepancy between the NIPT results and the amniocentesis results.
2. Disappeared Twins
Dissolution of twins (VT), first described in 1976, is the disappearance of the embryo or gestational sac following fetal cardiac activity that has been observed in both fetuses in a twin pregnancy. The incidence of VT has been shown to range from 10% to 39% in IVF pregnancies, while the rate of spontaneous pregnancy VT is still unclear. Cases of VT have been reported to be associated with adverse perinatal outcomes as well as an increased incidence of fetal malformations.
The presence of VT can affect NIPT test results, studies have shown that cfDNA from aborted twins can still be present in the mother's plasma at least 8 weeks after the termination of pregnancy and possibly up to 15 weeks (Figure 2). We know that chromosomal abnormalities are a major cause of miscarriage, and trisomy can be the cause of VT, which in turn can lead to false-positive NIPT results.
 
A recent study suggested that pregnant patients with VT should have a NIPT test 8 weeks after detection of VT. The study showed that, because the fetal fraction (FF) of VT was significantly reduced during these weeks and no longer affected NIPT results. However, this cannot be achieved when a woman's first obstetrician visit is too late to confirm pregnancy, a few weeks after the signs of twin pregnancy have disappeared. Therefore, it is recommended that pregnant women see their first obstetrician as soon as possible.
3. Malignancy in the mother
Maternal malignancy is relatively rare during pregnancy, with an incidence of 1 in 1000 pregnancies. In particular, according to statistics, breast cancer, liver cancer, lymphoma and stomach cancer are the most common cancers in pregnant women.
Studies have shown that underlying malignancies in the mother may provide a biological explanation for some of the contradictory NIPT results. Because cfDNA is released into the maternal circulation from programmed cell death (Figure 3).
These cfDNAs made the total maternal cfDNA increase, when the software compares with the reference sample and reads the results, it will easily give the NIPT result erroneous. If the mother's malignancy is not confirmed detected before pregnancy, this would be a contributing factor to false-positive NIPT results. In addition, there are also a few studies that report maternal malignancy through NIPT testing. Because one theory is that, when the risk of birth defects in the fetus is increased, there is a potential risk due to the occurrence of malignancy in the mother.

4. Mosaic chromosome in mother
Like maternal malignancy, maternal chromosomal mosaicism is also a factor in false-positive NIPT results with a similar principle. Maternal mosaicism can increase the amount of cfDNA in abnormal cells and in total cfDNA circulating in the maternal blood. If the mother's condition is not detected before pregnancy, the results may mistake the abnormality for the fetus.
Some recommendations are given to overcome this situation that pregnant women should be thoroughly examined before pregnancy as well as sharing about current medical conditions, family history is extremely important to Pregnancy management is carried out in the most favorable way.
Besides biological factors affecting NIPT test results, technical factors such as the technology platform used are also a factor affecting the accuracy of the test. Next-Generation Sequencing (NGS) technology on the NextSeq 550 sequencer system from Illumina, USA is a proven technology platform with more than 99% accuracy, less than 0.1% failure rate.
The data provided by Illumina suppliers is made on a large clinical database, and this is also a technology platform that is voted by the worldwide community of scientists as the technology company used in the field. Scientific research, development of tests in the field of molecular biology the most.
GENTIS is a genetic analysis unit in Vietnam that uses Illumina technology for NIPT testing. In addition, the GENTIS R&D team has successfully developed an advanced bioinformatics software that optimizes the readability of the results, thereby improving the accuracy of the NIPT test.
Although the NIPT test, although highly accurate, is still a screening test, factors that can lead to biased results have also been presented and reported. This again emphasizes the importance of more careful ultrasound and pregnancy monitoring to limit unwanted outcomes. Through the article, we hope that we have provided useful information to clinicians, thereby helping doctors have more timely and appropriate advice and indications for pregnant women.
References:
[1] van der Meij K. R. M., Sistermans E. A., Macville M. V. E., Stevens S. J. C., Bax C. J., Bekker M. N., et al. (2019). TRIDENT-2: National implementation of genome-wide non-invasive prenatal testing as a first-tier screening test in The Netherlands. Am. J. Hum. Genet. 105, 1091–1101. 10.1016/j.ajhg.2019.10.005
[2] Kleinfinger, Pascale et al. “Noninvasive Prenatal Screening for Trisomy 21 in Patients with a Vanishing Twin.” Genes vol. 13,11 2027. 3 Nov. 2022, doi:10.3390/genes13112027
[3] Gug, Cristina et al. “Genetic Counseling and Management: The First Study to Report NIPT Findings in a Romanian Population.” Medicina (Kaunas, Lithuania) vol. 58,1 79. 5 Jan. 2022, doi:10.3390/medicina58010079
[4] Lenaerts, Liesbeth et al. “Noninvasive Prenatal Testing and Detection of Occult Maternal Malignancies.” Clinical chemistry vol. 65,12 (2019): 1484-1486. doi:10.1373/clinchem.2019.306548
[5] Snyder MW, Simmons LE, Kitzman JO, et al. Copy-number variation and false positive prenatal aneuploidy screening results. N Engl J Med 2015; 372:1639–45
[6] Grömminger, Sebastian et al. “Fetal Aneuploidy Detection by Cell-Free DNA Sequencing for Multiple Pregnancies and Quality Issues with Vanishing Twins.” Journal of clinical medicine vol. 3,3 679-92. 25 Jun. 2014, doi:10.3390/jcm3030679
[7] Grati, F R. “Implications of fetoplacental mosaicism on cell-free DNA testing: a review of a common biological phenomenon.” Ultrasound in obstetrics & gynecology: the official journal of the International Society of Ultrasound in Obstetrics and Gynecology vol. 48,4 (2016): 415-423. doi:10.1002/uog.15975
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