False positive and false negative results may occur. A Case of False Negative NIPT for Down Syndrome-Lessons Learned @article{Smith2014ACO, title={A Case of False Negative NIPT for Down Syndrome-Lessons Learned}, author={Meagan Smith and Kimberly Lewis and A. Holmes and J. Visootsak}, journal={Case Reports in Genetics}, year={2014}, volume={2014} } DOI: 10.1155/2014/823504 Corpus ID: 787250. The risk of false negative screening tests is lower than for false positive screening tests, but is never nullified. 6. What are the chances that my NIPT is a false negative? Mathew, NIPT is only a screening so there is small probability of getting a false positive, false negative or even a no result. We’re waiting for the microarray results next week. Good news is that my NIPT came back low risk and Level 2 ultrasound at 19w2d looks great; my MFM looked over everything very carefully as she was the same doc who had done it for my T21 pregnancy. I just did a search and found one case report in 2014 of a false negative with Verifi for T21. NIPT as a screening test implies the occurrence of both false positive and negative findings, and all positive screening tests need further diagnostic invasive tests to verify or reject the positive screening result from the NIPT. Despite the low risk NIPT & good level 2, I feel worried. This test will not identify other abnormalities of … b) Testing is limited to the chromosomes and conditions listed above. Positive results should be confirmed by direct fetal testing. Does an NIPT pick up mosaic T21? I’m worried that the amnio microarray will miss microdeletions / microduplications. ... A negative result from a sample with a low fetal fraction is a valid result but there is an increased chance of a false-negative when compared to a negative result from a sample with a higher fetal fraction." I got my NIPT results back and everything looks good. Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the “fetal” DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk. There was 1 case of Trisomy 21 that had a normal NIPT result (false negative result), however negative test results were not methodically followed-up, so the true false negative rate for the screened conditions is unknown. The baby had a pretty significant heart abnormality seen on ultrasound and the mom opted for NIPT rather than an amnio, and the NIPT came back low risk. CVS and amniocentesis are the ONLY diagnostic tests which will tell your conclusively if there is any chromosome abnormalities. NIPT (MaterniT21 Genome) and Amnio karyotype were negative for abnormalities, but I believe these only test for issues sized over 7MB. Limitations of NIPT include: a) This is a screening test, not a diagnostic test.