Non-invasive prenatal test (NIPT)

Test for the screening for Down syndrome (trisomy 21), Edwards syndrome (Trisomy 18) and Patau syndrome (trisomy 13) in the baby by analyzing DNA of the baby in the blood of the mother.


Centre for human genetics

In our center, we also offer NIPT for women residing abroad.

Detection in the blood of the mother

NIPT is a non-invasive screening test for the detection of:

  • Down syndrome (trisomy 21)
  • Edwards syndrome (trisomy 18)
  • Patau syndrome (trisomy 13)

Are you considering NIPT for other reasons? You should first discuss this with your physician. For other specific genetic disorders, an alternative type of genetic testing may be more appropriate.

How does the NIPT work?

  • Small quantities of DNA of the baby circulates in the blood of the mother.
  • In general, sufficient DNA of the baby is present from 12 weeks of gestation onwards.

The NIPT determines:

  • Whether or not the baby has an extra copy of chromosome 21, 18 or 13.
  • The sex of the baby.


  • Only a blood sample from the mother is required.
  • No increased risk for a miscarriage.
  • No risk for the mother or her baby.


  • Since November 2013, over 100,000 analyses have been completed successfully in our center.
  • NIPT has an unprecedented sensitivity for detection of trisomy 21, 18 and 13 in the baby.
  • In some cases, the NIPT result is false positive.
    • In this case the test results indicate that the baby has a trisomy, whereas this is not true.
    • An abnormal test result should therefore always be confirmed by an invasive test (preferably by amniocentesis).

The NIPT performed within the center of human genetics in Leuven is an in-house optimized and validated test and has been published in various scientific journals. Our laboratory is accredited for performing NIPT according to the ISO-15189 quality standard via BELAC (215-MED).

Our center also provides multidisciplinary expertise that guarantees the correct interpretation and follow-up of NIPT in accordance with the national guidelines of the Belgian Society of Human Genetics (BeSHG) and the advice of the Belgian Advisory Committee on Bioethics (Opinion No. 66).

An overview of the diagnostic experience and performance of the NIPT in UZ Leuven can be found here.

Rare incidental findings

Using NIPT, all chromosomes are analyzed. Therefore, in rare cases, NIPT can also reveal other chromosomal abnormalities, for example:

  • A trisomy of a chromosome other than 13, 18 or 21.
  • A chromosome abnormality in the mother that is important for her own health or for that of her baby.
  • Specific small chromosome abnormalities in the baby (read more).
  • Some types of cancer in the mother.

In either one of these cases,one of our centers’ clinical geneticists will inform you and your physician accordingly. Please note that NIPT is currently not able to detect all cases of these rare incidental chromosome abnormalities.


  • From the 12th week of gestation onwards.
  • Only if, during this pregnancy, NIPT has not already been performed and reimbursed by the public health insurance.

Please provide the following information on the request form for correct interpretation of the test results:

  • Monozygotic or dizygotic twin pregnancy or multiple pregnancy (identical and non-identical twins).
  • Pregnancy with a ‘vanishing twin’ (original twin pregnancy with one baby deceased early in pregnancy).
  • The weight of the mother prior to the pregnancy exceeded 100 kg.
  • The mother has (had) cancer.
  • The mother has lupus.
  • The mother is on heparin therapy.


NIPT is not appropriate in case of:

  • Ultrasound abnormalities in your baby (including a nuchal translucency thickness exceeding 3.5mm).
  • The mother has had one of the following treatments:
    • Stem cell therapy
    • Organ transplant

Limitations of NIPT

NIPT is not able to detect:

  • Mosaic trisomy 21, 18 or 13 (not all the cells have a trisomy)
  • Small chromosome abnormalities (microdeletions or microduplications)
  • Monogenic (single gene) disorders (such as cystic fibrosis or fragile X syndrome)
  • Numerical abnormalities of the sex chromosomes (such as Turner syndrome or Klinefelter syndrome)


The result will be available after 7 calendar days counting from the receipt of the blood sample in our laboratory.

The results can be consulted in your online medical file through ‘mynexuzhealth’. You will also receive a hard copy of these results. In case of an abnormal result, one of our centers’ clinical geneticists will inform both you and your physician.

Possible test results

  • Normal: there is no indication for the presence of trisomy 21, 18 or 13 in the baby.
  • Abnormal: there is a strong suspicion of the presence of trisomy 21, 18 or 13 in the baby.
    • To have complete certainty, an abnormal NIPT result should always be confirmed by an invasive test, preferably by amniocentesis.
  • Inconclusive: In rare cases, the NIPT cannot reliably estimate the risk of either trisomy 21, 18 or 13 in the baby. This does not necessarily mean that there is an increased risk of trisomy 21, 18 or 13. In most cases, the presence of a trisomy 21, 18 or 13 can be excluded by repeating the NIPT on a second blood sample (free of charge). You can visit your physician should you wish to have the NIPT repeated or to discuss whether further ultrasound follow-up is appropriate.

  • Not interpretable: Exceptionally, the NIPT fails to provide a reliable result. This can be caused, for example, by a technical reason or because there is too little DNA from the baby in the mother's blood. This does not necessarily mean that there is an increased risk of trisomy 21, 18 or 13. In most cases, a second NIPT test on a new blood sample (free of charge) does provide a reliable result. You can visit your physician to have a new blood sample taken or to discuss whether further ultrasound follow-up is appropriate.

    If too little DNA from the baby was present in the first blood sample, we recommend that the new blood sample is only taken from 14 days after the first blood sample. In this way, the chance of a reliable test result is much higher.

  • Incidental findings that are important for the health of the mother and/or the baby: because NIPT analyses all chromosomes, in rare cases it can also detect other chromosomal abnormalities (see above). Should this be the case, your physician or one of our centers’ clinical geneticists will inform you accordingly and offer you the necessary multidisciplinary care.


NIPT is reimbursed in Belgium.

  • Hence, pregnant women who are a member of a Belgian service for public health insurance only pay € 8,68 for the laboratory test.
  • In case of an increased allowance, the NIPT is free of charge.
  • In other cases, your personal cost for the laboratory test is € 246,59.

For a genetic consultation, an additional cost will be charged.

  • In case you are a member of a Belgian service for public health insurance, the additional cost is € 12.
  • In case of an increased allowance, the additional cost is € 3.
  • In other cases, an additional € 43,69 will be charged for the genetic consultation.

Use of genetic data for scientific research

The center of human genetics of UZ Leuven is committed to continuously improve the quality of our care and testing. With the permission of the ethics committee, the residual material and genomic data obtained after NIPT can be used for validation, internal quality control or research purposes (for example, optimization of the NIPT and new developments). An overview of the current research projects can be found here.


    For professionals

    Extra information

    Last edit: 27 October 2022