OBJECTIVES: The aim of the study was to present initial results of non-invasive 
prenatal diagnosis of common aneuploidies of chromosomes 21, 18 and 13 based on 
cell-free fetal DNA in maternal serum in high-risk patients, and to compare the 
results with routine karyotyping.
MATERIAL AND METHODS: Before the invasive procedure, 10 ml of peripheral blood 
from 10 patients was collected to isolate cell-free fetal DNA and to perform a 
non-invasive fetal trisomy test (NIFTY provided by Beijing Genomics Institute, 
BGI, Shenzen, China).
RESULTS: Three out of 10 samples showed an abnormal karyotype in traditional 
karyotyping. There were 9 conclusive NIFTY results. NIFTY detected 1 out of 2 
trisomies 18. The quantity of cell-free fetal DNA in maternal plasma in the 
second probe with trisomy 18 was unsatisfactory fora conclusive NIFTY result. In 
1 case traditional karyotyping revealed mosaicism impossible to detect with 
NIFTY