Non Invasive Prenatal Test

About NIPT
Methodology
Minimum 
requirements
Compatible platforms
& Kits

About NIPT

 

During pregnancy, fragments of the baby's DNA circulate in the mother's blood stream. By measuring the number of these DNA fragments, the number of chromosome 21, 18 and 13 copies can be determined. Thus, trisomy 21, 18 or 13 can be detected in the baby. The blood sample should be collected at a minimal gestational age of 11 weeks to ensure a sufficient amount of the baby’s DNA circulating in the mother’s blood.
The NIPT has a sensitivity of more than 99%, which means that more than 99 out of 100 babies with trisomy 21, 18 and 13 will be detected by this test, while 1 or fewer will be missed. For 1% the NIPT will lead to a false positive result. This means that when 100 women take the test, 1 of them will be told that there is an increased risk of trisomy 21, even though her baby does not have trisomy 21. NIPT was developed in our laboratories with the utmost attention to quality (as for all other genetic analyses) and obtained accreditation from Belac (Belgian Accreditation institution) for detection of trisomy 21, 18 and 13.

 

For more information about NIPT, please see our information leaflet or contact us.

 

BELAC 141-MED accredited according

to quality norm ISO 15189:2012

Methodology

 

Maternal blood is collected in Streck Cell-Free DNA BCT tubes and cell free DNA (cfDNA) is isolated from the plasma fraction. The isolated cfDNA consists of both maternal as fetal DNA fragments.

The 3' and 5' overhangs of the cfDNA are blunt ended by resp. a 3' exonuclease and a DNA polymerase, followed by 5' adenylation (polynucleotide kinase) in order to generate a substrate for the adapter ligation.

Next, a PCR amplification step is performed to generate sufficient yield for Massive Parallel Sequencing (MPS) on the HiSeq, generating 1x50bp reads.

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Minimum requirements

Following are the minimum requirements for us to proceed with NIPT :

  • Completed and signed request form and informed consent

  • Streck cell-free DNA BCT tube, taken from mother at a minimal gestational age of 11 weeks

 

When am I eligible for the NIPT :

  • You have had the first trimester combined test performed, showing an increased risk of trisomy 21, 18 or 13 (>1/300)

  • You have had a previous pregnancy with trisomy 21, 18 or 13

  • You are 40 years or older and therefore have a strongly increased risk of having a baby with trisomy 21, 18 or 13 because of your age

  • You are very worried and would like as much certainty as possible on trisomy 21, 18 or 13 without having an invasive test

  • You don't have an increased risk, but want to minimize the residual risk for trisomy 21, 18 or 13 and avoid the risk of miscarriage related to an invasive test

  • You have other reasons than the aforementioned for considering the NIPT. These reasons should be discussed with your doctor because certain genetic conditions require different tests

 

When am I not eligible for the NIPT :

  • NIPT is NOT possible (first trimester combined test preferred) in case of :

    • A dizygotic twin pregnancy or multiple pregnancy

    • Previous blood transfusion (< 3 months ago), stem cell therapy, immunotherapy or transplant in the mother

    • Anomalies in the genetic material of the mother or father

  • An invasive test is preferable in case of :

    • Sonographic abnormalities in the baby (including neck fold measurement of >3.5mm)

    • (Severely) overweight mothers

Compatible platforms

 

All NIPT runs are performed on the Illumina HiSeq, generating 1x50bp reads.

Kits

The kits used to perform the NIPT test are non-disclosed.

BRIGHTcore / T +32 (0)2 477 64 79 / F +32 (0)2 477 68 59 / © 2015 by BRIGHTcore

Photography / Bart Moens / http://www.fotobart.be

Content & illustrations / Ben Caljon