Non-invasive fetal trisomy (NIFTY) test in prenatal diagnosis

Abstract

NIFTY (Non-invasive Fetal Trisomy Test) is a non-invasive prenatal test which is used for diagnosing fetal trisomy. The test is based on the analysis of cell free fetal DNA (cffDNA) present in the plasma and serum of a pregnant woman. NIFTY allows to detect fetal trisomy of chromosomes 13, 18, 21, X and Y and also X monosomy. Abnormal NIFTY results still need to be verified using other diagnostic techniques. However the sensitivity of NIFTY for trisomy 21, 18 and 13 is estimated at 99%, 97% and 79% respectively with false positive rate for all examined trisomies and X monosomy of < 1%. NIFTY is currently available in Poland as a commercial service, used as a good screening test for common trisomies (apart from ultrasound and biochemical tests) in the case of patient anxiety and in situation when the patient does not consent to invasive prenatal diagnostic tests. The sensitivity and specificity of NIFTY will most likely be improved as laboratory methods develop, and after a sufficiently large group of pregnant patients has been tested. Therefore, this test may soon become the primary diagnostic tool for common trisomies, allowing to avoid invasive prenatal testing in this indication. With high probability cffDNA obtained from the serum of pregnant women will also be used with time in the diagnosis of fetal structural chromosomal aberrations and other genetic changes. The aim of our study is to present a new diagnostic method.