Prenatal Screening: Are all non-invasive prenatal tests the same?

24 October 2019

prenato, femme enceinte, grossesse, prengnancy, adn, génétique, trisomie 21

Non-invasive prenatal testing (NIPT) using cell-free DNA allows for faster and more accurate screening than both the Quebec prenatal screening program for trisomy 21 and the different hormone-based screening tests offered in private clinics. NIPT using cell-free DNA is a test that can screen for multiple genetic anomalies from just one blood sample from the mother as early as the 10th week of pregnancy. These tests are reliable up to 99.9% and can provide results in the first trimester of pregnancy.


Different laboratories offer different tests depending on the private clinic you choose for your prenatal testing. But are all these tests the same? To answer this question, we asked the opinion of Andrea Secord, certified genetic counsellor. Here is her response: First, the efficiency of the test, the reliability of the results and the speed of the analysis will all be influenced by the DNA sequencing method and the location of the analysis. So that means that these tests are not all equivalent. Andrea recommends choosing a test that is analyzed in North America and whose method of sequencing allows the lowest failure rate. A failure in the analysis of the blood sample occurs when the laboratory is unable to provide a result. Some risk factors increase the rate of failure, including in vitro fertilization, maternal obesity and certain other medical conditions of the mother. In 22% of cases, a test failure hides a genetic anomaly, so the recommendation for such a situation is to refer the expectant mother for amniocentesis. The failure rate varies between 0.1% and 6% depending on the sequencing method and the chosen laboratory. Since the goal of NIPT is to avoid an amniocentesis, it is important to choose a test with a low failure rate.


Here are the questions that future parents should ask themselves before choosing a prenatal screening test by cell-free DNA:


What is the failure rate of the test?
How long does the analysis of the blood sample take?
Where will the blood sample be analyzed?
How will the results be given to future parents and to the health care professional following the pregnancy?
How reliable are the results?


In order to support a free and informed choice, your health care professional should be able to answer these questions before referring you to a prenatal screening test using cell-free DNA.


The Premium Plus (Verifi) and Signature (Verifi+) tests offered by Prenato are reliable up to 99.9%, have a failure rate of 0.1% and are analyzed in California. The results are received on average in 5 working days and will be given to you directly by telephone by a Prenato nurse. A copy of your result will also be sent to your health care professional. If the result is abnormal, your health care professional will contact you to explain your result and the Prenato team will ensure your case will be taken care of quickly.


Contact us for more information 1-866-362-8602


Photo by Camylla Battani 

Les informations fournies sur cette page le sont à titre indicatif seulement et ne constitue en aucune circonstance une démarche de diagnostic ou d’évaluation médicale quelconque. En tant qu’utilisateur, vous reconnaissez que vous ne pouvez vous fier à l’information contenue sur cette page pour votre propre santé ou condition.

Prenato ne fait aucune représentation ou garantie, qu’elle soit expresse ou implicite, concernant l’exactitude, l’exhaustivité, l’actualité, le caractère comparatif ou l’utilité de toute information contenue ou mentionnée sur cette page. Puisque l’information relative au domaine de la santé évolue constamment, celle contenue sur cette page pourrait être ou devenir désuète, incomplète ou incorrecte. L’utilisation de ce site ne saurait constituer une relation « médecin-patient ». Toute question visant votre santé devrait être adressé à votre médecin ou à un autre professionnel de la santé.

En utilisant ce site, vous reconnaissez que Prenato ne pourra en aucune circonstance être tenue responsable de toute décision, geste ou action posé par vous en lien avec l’information contenue aux présentes.

Aucune reproduction du contenu n’est autorisé sans le consentement préalable et écrit de Prenato.