Test introduction Detection advantage Testing process For people
Technical brief



1. What is Non-Invasive Prenatal Test /NIPT?

Non-Invasive Prenatal Test /NIPT is a new test technology for fetal chromosome aneuploidy disease, which is non-invasive, reliable, convenient and fast. The high incidence 21-trisomy syndrome (Down syndrome), 18-trisomy syndrome (Edward  syndrome), and 13-trisomy syndrome (Patau syndrome) are all included.


Fig 1: Application scope of non-invasive prenatal DNA testing

2. Technical principle

In 1997, scientists discovered the presence of fetal free DNA in maternal peripheral blood, and this finding became the theoretical basis for noninvasive prenatal test [1]. Non-Invasive Prenatal Test /NIPT technology collects free DNA fragments from maternal peripheral blood then use the next generation sequencing technology and combines bioinformatics analysis and data statistics to finally assess whether the fetus is suffering from three major chromosomal diseases, including 21-trisomy syndrome (Down syndrome), 18-trisomy syndrome (Edward syndrome) and13-trisomy syndrome (Patau syndrome).


Fig 2: Cell-free fetal DNA contained in mother’s peripheral blood

Taking Down syndrome test as an example, the study found that as for the fetal DNA in the peripheral blood of gravida, because the fetus of Down syndrome has one more chromosome 21 than the normal fetus, so that the level of chromosome 21 in the peripheral blood of gravida with Down syndrome is slightly higher than that of normal gravida.

Through testing the relative content of chromosome 21 in the peripheral blood of pregnant women directly, and analyzing the level of chromosome 21 in the peripheral blood of the examinee and the general pregnant population, the risk of the fetus’birth of Down syndrome can be further obtained. Combined with the next generation of high-throughput sequencing technology, the test sensitivity and accuracy are improved greatly, and the test period is also shortened greatly.




1. Preparation of test

You don’t need an empty stomach before blood drawing, you can keep your normal diet.

2. Test period

A professional test report will be issued within 7-10 working days.

3. Considerate insurance

To make every gravida to take the test with safety, Annoroad provide insurance for all gravida to be tested.

Technical advantages

As the first batch of high-throughput sequencing clinical application pilot organizations approved by the National Health and Family Planning Commission, Annoroad is one of the early companies entering the field of non-invasive prenatal test. Annoroad has extensive cooperation with major hospitals around the country and has accumulated a large amount of clinical data and project experience. Non-Invasive Prenatal Test /NIPT technology is one of Annoroad’s important projects focusing on health and promoting people’s livelihood. With the support of relevant national policies and regulations, it will assist clinical experts to accurately and efficiently complete the test of fetal chromosome aneuploidy diseases better.


Testing process


For people

Applicable People


Non-invasive prenatal DNA test is suitable for single-pregnant women who are pregnant for more than 12+0 weeks. The target disease is common fetal chromosome aneuploidy disease (containing 21-trisomy, 18-trisomy, 13-trisomy syndrome).


1. Serological screening shows that the common chromosome aneuploid risk value of the fetus is between the high risk cut value and 1 / 1000 gravidas.

2. Patients with interventional prenatal diagnosis contraindications (such as threatened abortion, fever, bleeding tendency, chronic pathogen infection active period, pregnant Rh-negative blood type, etc.).

3. Pregnancy 20+6 weeks or more, missed the best time for serological screening, but asked to assess the risk of trisomy 21, trisomy 18, trisomy 13 syndrome.

Gravidas who have the following conditions should use the method with caution, including:


1. Prenatal screening for high risk in early and middle pregnancy.

2. Age ≥ 35 years old.

3. Severe obesity (body mass index > 40).

4. Pregnancy by in vitro fertilization - embryo transfer.

5. Gravidas have chromosome abnormality of the fetus delivery history, but except for the couple’s chromosomal abnormalities.

6. Twin and multiple pregnancies.

7. Other circumstances that the physician believes may affect the accuracy of the results.


Inapplicable People:

1. Gestational weeks <12 +0 weeks.

2. One side of the couple has a clear chromosomal abnormality.

3. Received allogeneic blood transfusion, transplant surgery, allogeneic cell therapy within 1 year

4. Fetal ultrasound examination indicates that structural abnormalities require prenatal diagnosis.

5. There is a family history of genetic diseases or suggest that the fetus is at high risk of genetic diseases.

6. Combined with malignant tumors during pregnancy.

7. The physician believes that there are other situations that significantly affect the accuracy of the results.

Except for the above-mentioned non-applicability, gravidas or their families may choose non-invasive prenatal DNA testing with full and informed consent.

Technical Specifications for Prenatal Screening and Diagnosis of Fetal Free DNA in Gravidas’ Peripheral Blood

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